Question

Perimeter of a sector of a circle whose
central angle is 90° and radius 7 cm is
(a) 35 cm
(b) 25 cm
(c) 77 cm
(d) 7 cm
a
b
C
O
d​

Answer 1

GIVEN :-

• Central angle = 90°.
• Radius = 7 cm.

TO FIND :-

• The perimeter of sector of Circle.

SOLUTION :-

As we know that the perimeter of a sector of a Circle is given by,

⇒ Perimeter = ϴ/360° × 2πr + 2r

• ϴ = Central angle.
• r = Radius.
• π = 22/7.

⇒ Perimeter = 90°/360° × 2 × 22/7 × 7 + 2 × 7

⇒ Perimeter = 1/4 × 2 × 22 + 14

⇒ Perimeter = 1/4 × 44 + 14

⇒ Perimeter = 11 + 14

⇒ Perimeter = 25

Hence the perimeter of the sector of the Circle is 25 cm.

Option ( b ).

Answer 2

Answer:

The answer is 25cm.

Step-by-step explanation:

Perimeter of sector of a circle = 2r + 2πr* Ф/360°

By substituting the values, we get:

⇒ 2*7 + 2 * 22/7 * 7 * 90°/360°

⇒ 14 + 2 * 22 * 1/4

By taking LCM as 4, we get:

⇒ 56 + 44 / 4

⇒ 100/4

⇒ 25

Hope this helps you:)