# DAV Class 7 Maths Chapter 11 Worksheet 3 Solutions

The DAV Maths Class 7 Solutions and DAV Class 7 Maths Chapter 11 Worksheet 3 Solutions of Perimeter and Area offer comprehensive answers to textbook questions.

## DAV Class 7 Maths Ch 11 WS 3 Solutions

Question 1.
One side of a parallelogram is 14 cm. Its distance from the opposite sides is 16.5 cm. Find the area of parallelogram.
Area of the parallelogram
= Base x Distance between the parallel sides
= 14 cm x 16.5 cm
= 231 cm2

Question 2.
A parallelogram has a base of 135 dm. The corresponding height is 6 cm. Find the area of the parallelogram in square metres.
im-1
Area of the parallelogram = Base × Height
= 135 dm x 6 dm
= 810 dm2
= 8.10 m2
Hence the required area = 8.1 m2 .

Question 3.
The altitude of a parallelogram corresponding to a base of length 15 cm is 18 cm. Find the area of the parallelogram.
Area of the parallelogram = Base × Altitude
= 15 × 18 = 270 cm2
Hence the required area = 270 cm2. Question 4.
The height of parallelogram is 3 dm. If the area is 240 cm2, find the base of the parallelogram.
Height h = 3 dm = 30 cm and area = 240 cm2
Area of parallelogram = Base × Height
240 = Base × 30
Base = $$\frac{240}{30}$$ = 8 cm
Hence the required base = 8 cm.

Question 5.
Find the area of rhombus whose one side is 8 cm and altitude is 0.6 dm.
One side of rhombus = 8 cm
Altitude = 0.6 dm = 0.6 × 10 = 6 cm
Area = Side × Altitude = 8 × 6 = 48 cm2
Hence the required area = 48 cm2.

Question 6.
Find the altitude of a rhombus whose area is 320 m2 and side is 5 m.
Area of rhombus = 320 m2 and side = 5 m
Area = side × altitude 320 = 5 × altitude
∴ Altitude = $$\frac{240}{30}$$ = 64 cm
Hence the required altitude = 64 cm.

Question 7.
The height of parallelogram is one-third of its base. If the area is 108 cm2, find the base and height.
Let the base be x cm
its height = $$\frac{1}{3}$$ x cm
Area = base × height
⇒ 108 = x × $$\frac{1}{3}$$x
⇒ 108 = $$\frac{x^2}{3}$$
⇒ x2 = 108 × 3
⇒ x2 = 324
x = 18 cm
Hence base = 18 cm and the height = 18 × y = 6 cm.

Question 8.
The area of a rhombus is 119 cm2 and its perimeter is 56 cm. Find its altitude.
Perimeter of rhombus = 56 cm.
Its one side = $$\frac{56}{4}$$ = 14 cm
Area = side × altitude 119
= 14 × altitude
Altitude = $$\frac{119}{14}$$ = 8.5 cm
Hence the required altitude = 8.5 cm. Question 9.
One side and corresponding altitude of a parallelogram are 50 an and 8 cm. If the other altitude is 4 cm, find the length of the other pair of parallel sides.
Area of the parallelogram = Side × corresponding altitude
= 50 × 8 = 400 cm2
Now other altitude corresponding to other side = 4 cm
Area = Side × Altitude
400 = Side × 4
∴ Side = = 100 cm
Hence the required side = 100 cm.

Question 10.
Area of a parallelogram is 625 m2. Find the length of sides of parallelogram if altitude corresponding to sides are 20 m and 25 m.
x = $$\frac{625}{20}$$ = 31.25 m
∴ y = $$\frac{625}{20}$$ = 25 m