Question

5 innovative mensuration problems class 8

Answer 1

Answer:

Step-by-step explanation:

Solution:

(i) Perimeter of the rectangle = 2(l + b) = 2(8 + 6) = 2 × 14 = 28 cm

(ii) Perimeter of the square = 4 × side = 4 × 6 = 24 cm

(iii) Perimeter of the circle = 2πr = 2 × \frac { 22 }{ 7 } × 7 = 44 cm.

Question 2.

The length and breadth of a rectangle are 10 cm and 8 cm respectively. Find its perimeter if the length and breadth are (i) doubled (ii) halved.

Solution:

Length of the rectangle = 10 cm

Breadth of the rectangle = 8 cm

(i) When they are doubled,

l = 10 × 2 = 20 cm

and b = 8 × 2 = 16 cm

Perimeter = 2(l + b) = 2(20 + 16) = 2 × 36 = 72 cm

(ii) When they are halved,

l = \frac { 10 }{ 2 } = 5 cm

b = \frac { 8 }{ 2 } = 4 cm

Perimeter = 2(l + b) = 2(5 + 4) = 2 × 9 = 18 cm

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