Edudel, Directorate of Education Govt. of NCT of Delhi Class 8 Mental Maths Question Bank Chapter 15 Introduction to Graphs Questions Solution. In this chapter, there are total 50 math problems. We have given each questions solution step by step.
Edudel Class 8 Mental Maths Chapter 15 Introduction to Graphs:
1.) Where does the point (8, 0) lie?
ANSWER:
We know,
When y axis coordinate is 0 then points lies on x axis.
The point (8, 0) lies on x axis.
2.) Where does the point (0, 9) lie?
ANSWER:
We know,
When x axis coordinate is 0 then points lies on y axis.
The point (0, 9) lies on y axis.
3.) What is abscissa of the point (3, 4)?
ANSWER:
The abscissa of the point (3, 4) is 3.
4.) What is the ordinate of the point (6, 7)?
ANSWER:
The ordinate of the point (6, 7) is 7.
5.) What are the coordinates of the origin?
ANSWER:
The coordinates of the origin is (0, 0)
6.) What is the perpendicular distance of the point (7, 8) from x-axis?
ANSWER:
We know,
The perpendicular distance of the point from x-axis is y axis coordinate.
The perpendicular distance of the point (7, 8) from x-axis is 8 units.
7.) What is the perpendicular distance of the point (4, 5) from y-axis?
ANSWER:
We know,
The perpendicular distance of the point from y-axis is x axis coordinate.
The perpendicular distance of the point (4, 5) from y-axis is 4 units.
8.) What is the shortest distance of the point (6, 8) from origin?
ANSWER:
We have to find the shortest distance of the point (6, 8) from origin
By Pythagoras theorem,
62+ 82 = 100
100 = 102
The shortest distance of the point (6, 8) from origin is 10 units.
9.) What is the shortest distance of the point (7, 0) from origin?
ANSWER:
We have to find the shortest distance of the point (7, 0) from origin.
When y coordinate is 0, then the shortest distance of the point is x coordinate.
The shortest distance of the point (7, 0) from origin is 7 units.
10.) What is the shortest distance of the point (0, 8) from origin?
ANSWER:
We have to find the shortest distance of the point (0, 8) from origin
When x coordinate is 0, then the shortest distance of the point is y coordinate.
The shortest distance of the point (0, 8) from origin is 8 units.
11.) What is the shortest distance between the points (14, 3) and (9, 3)?
ANSWER:
We have to find the shortest distance between the points (14, 3) and (9, 3)
The shortest distance between the points (14, 3) and (9, 3) = (14 – 9) and (3-3)
The shortest distance between the points (14, 3) and (9, 3) = (5, 0)
When y coordinate is 0, then the shortest distance of the point is x coordinate.
The shortest distance between the points (14, 3) and (9, 3) is 5 units.
12.) What is the distance of the point (3, 4) from origin?
ANSWER:
We have to find the distance of the point (3, 4) from origin.
By Pythagoras theorem,
32+ 42 = 25
25 = 52
The distance of the point (3, 4) from origin is 5 units.
13.) Find the distance between two points P (4, 0) and Q (9, 0).
ANSWER:
We have to find thedistance between two points P (4, 0) and Q (9, 0).
Distance between two points P (4, 0) and Q (9, 0) = (9-4)
Distance between two points P (4, 0) and Q (9, 0) is 5 units.
14.) Find the distance between two points A(0, 3) and B(0, -9).
ANSWER:
We have to findthe distance between two points A (0, 3) and B (0, -9).
The distance between two points A (0, 3) and B (0, -9) = (3 – (-9))
The distance between two points A (0, 3) and B (0, -9) is 12 units.
15.) What are the coordinates of the points for which x=0 and y=x+2?
ANSWER:
We have to findthe coordinates of the points for which x=0 and y=x+2
We put x=0 in y=x+2
We get,
y = 0 + 2
y = 2
The coordinates of the points is (0, 2)
16.) What are the coordinates of the points for which y=0 and y=x+2?
ANSWER:
We have to find the coordinates of the points for whichy=0 and y=x+2.
We put y =0 in y=x+2
We get,
0=x+2.
X = -2
The coordinates of the points is (-2,0)
17.) To which axis will the line joining the points having x-coordinate constant will be parallel?
ANSWER:
To Y axis will the line joining the points having x-coordinate constant will be parallel
18.) To which axis will the line joining the points having y-coordinate constant will be parallel?
ANSWER:
To X axis will the line joining the points having y-coordinate constant will be parallel
19.) Name the point where two axes intersect?
ANSWER:
The point where two axes intersect is called origin point.
For Question no. 20 to 31, see the Graph_1
20.) What are the coordinates of points A and B?
ANSWER:
From graph,
The coordinates of points A and B are A (2, 0), B (0, 3).
21.) Which type of the quadrilateral KLMN is?
ANSWER:
From graph,
Type of the quadrilateral KLMN is square.
22.) What are the coordinates of K, L, M and N?
ANSWER:
From graph,
The coordinates of K, L, M and N are K (2, -3), L (4, -3), M (4, -1), N (2, -1)
23.) What type of quadrilateral PQRS is?
ANSWER:
From graph,
The type of quadrilateral PQRS isParallelogram
24.) What are the coordinates of the vertices of quadrilateral PQRS?
ANSWER:
From graph,
The coordinates of the vertices of quadrilateral PQRS are P(-6, -2), Q(-2, -2), R(2, 2), S(-2, 2)
25.) What is the area of quadrilateral KLMN?
ANSWER:
From graph,
Quadrilateral KLMN is a square.
The side of squareKLMN is 2 unit.
We know,
Area of square KLMN = (side) 2
Area of squareKLMN = (2) 2
Area of square KLMN = 4 unit2
26.) What type of △HIJ is?
ANSWER:
From graph,
Type of △HIJ is isosceles right angled triangle.
27.) What is the length of side IJ of △HIJ?
ANSWER:
From graph,
In △HIJ
Side IJ lies in point 3 to 7 on x axis.
Side IJ = 7 – 3 = 4
Side IJ = 4 units.
28.) What is the area of △HIJ?
ANSWER:
We have to find area of △HIJ.
We know,
Area of triangle = 1/2 x base x Height
Base = side IJ
Height= side HJ
From graph, base and Height is 4 units.
Area of triangle HIJ=1/2 x 4 x 4
Area of triangle HIJ = 8 unit2
29.) What are the coordinates of point C and D?
ANSWER:
From graph,
The coordinates of point C and D are C (2, 3) D (-4,-3)
30.) What is the length of the shorter side of the quadrilateral PQRS?
ANSWER:
We have to find the length of the shorter side of the quadrilateral PQRS
In quadrilateral PQRSshorter sides are PQ and RS.
From graph,
The length of the shorter side of the quadrilateral PQRS is 4 units.
31.) What is the distance between the points C and N?
ANSWER:
We have to find Distance between the points C and N.
We know,
Coordinates of point c is c (2, 3)
Coordinates of point N is N (2, -1)
Distance between the points C and N = (2 – 2, 3 – (-1))
Distance between the points C and N = (0, 4)
Distance between the points C and N is 4 units.
For question 32 to 40, see the Graph_2
32.) For what period of time does the graph show the temperature?
ANSWER:
From graph,
For 7 days (1 week) the graph show the temperature.
33.) The temperature in the beginning of the week was rising or falling?
ANSWER:
From graph,
The temperature in the beginning of the week was rising.
34.) What is the average temperature of fourth and fifth days?
ANSWER:
We have to find average temperature of fourth and fifth days.
From graph,
Temperature of fourth day = 300C
Temperature of fifth day = 400C
Average temperature of fourth and fifth days = 300C + 400C / 2
Average temperature of fourth and fifth days = 350C
35.) What is the difference between the highest and lowest temperature?
ANSWER:
We have to findthe difference between the highest and lowest temperature.
From graph,
Highest temperature = 400C
Lowest temperature. = 150C
The difference between the highest and lowest temperature = 400C – 150C
The difference between the highest and lowest temperature = 250C
36.) After which day temperature fell down drastically?
ANSWER:
From graph,
After 5thday temperature fell down drastically.
- Between which days was the change in temperature minimum?
ANSWER:
From graph,
Between 2nd and 3rd days was the change in temperature minimum.
38.) Between which days was the change in temperature maximum?
ANSWER:
From graph,
Between 5th and 6th days was the change in temperature minimum.
39.) What is the temperature on second day?
ANSWER:
From graph,
The temperature on second day is 22.50C
40.) On which days temperature is 25o Celsius?
ANSWER:
From graph,
On 3rd and 6th days temperature is 25o Celsius.
For question 41 to 48, see the Graph_3
41.) What is represented on x-axis?
ANSWER:
From graph,
On x-axis time (in hour) is represented.
42.) What is shown on y-axis?
ANSWER:
From graph,
on y-axisDistance between city A to B (in Km)
43.) From where and when the journey begins?
ANSWER:
From graph,
The journey begins from city A at 6 am.
44.) What is the distance covered in first hour?
ANSWER:
From graph,
The distance covered in first hour is 50 km.
45.) How much distance is covered in first 4 hours?
ANSWER:
From graph,
Distance is covered in first 4 hours i.e. in between 6 am to 10 am is 150 km.
46.) At what time the distance of 200km was covered?
ANSWER:
From graph,
At 11 am the distance of 200km was covered.
In 5 hours the distance of 200km was covered.
47.) At what time the driver take a break?
ANSWER:
From graph,
In between 9 am to 10 amthe driver take a break.
48.) When the journey ends and car reached city B?
ANSWER:
From graph,
At 3 pm the journey ends and car reached city B.
49.) On joining points x (0, 0), y (3, 0) and z (0, 3), which figure will you get?
ANSWER:
On graph, when we join points x (0, 0), y (3, 0) and z (0, 3).
We get shape of isosceles right angled triangle.
50.) On joining points A (3, 3), B (4, 4), C (5, 5) and D (6, 6), which figure will you get?
ANSWER:
On graph, when we join pointsA (3, 3), B (4, 4), C (5, 5) and D (6, 6),
We get shape ofStraight line.