Circle Area | MCQs

Explanation

Given the area A = 172.1 cm², and the formula for the area of a circle is A = πr²:

Step 1: Find the radius

172.1 = πr²

r² = 172.1 / π

r² = 172.1 / (22/7)

r² = 172.1 * (7/22)

r² = 54.77

r ≈ √54.77

r ≈ 7.4

Step 2: Calculate the circumference

Circumference C = 2πr

C = 2 * (22/7) * 7.4

C ≈ 2 * 3.14 * 7.4

C ≈ 46.51

Explanation

In geometry, the area enclosed by a circle of radius r is πr2

Arear of the circle: πR2

The perimeter of the circle: C = 2πR

Symmetry group: O(2)‎

Explanation

Let's consider the radius is r and therefore the Area will be πr².

Now the radius is increased by 4 times than the Area would be.

π(4r)² or the area would work to 16 times (4²=16).

Explanation

The area of the circle with radius 10 cm is A₁ = π(10)² = 100π cm².

The area of the circle with radius 10.1 cm is A₂ = π(10.1)² = 102.01π cm².

The percentage change in area is:

((A₂ - A₁) / A₁) × 100%

= ((102.01π - 100π) / 100π) × 100%

= (2.01 / 100) × 100%

= 4%

So, the percentage change in the area is 4%.

Explanation

Explanation