Question

The following figure is a combination of two semi-circles and a rectangle. If the radius of the circle is 21 cm and the length of the rectangle is 10 cm, the perimeter of the shape is :

• A. 152 cm
• B. 160 cm
• C. 132 cm
• D. 20 cm

Answer 1

Answer:

A. 152 cm

Solution:

Given:

Radius of the semicircle = 21cm

Length of the rectangle = 10cm

Formula used:

Circumference of a circle = 2πr

Calculation:

According to the diagram,

Perimeter of the shape is Sum of the circumference of two semicircles and the two length of the rectangle

Two semicircle = Circle

Circumference of the circle with radius 21cm $=2\times{\frac{22}{7}}\times{21}$

= 132 cm ----(1)

Two length of the rectangle = 2 × 10

= 20 cm ----(2)

Perimeter of the shape = (1) + (2)

= 132 + 20

= 152 cm

Answer is 152 cm.