2. What is the exact area of a circle with a diameter of 10 cm?

A. [tex]10\pi \, \text{cm}^2[/tex]
B. [tex]25\pi \, \text{cm}^2[/tex]
C. [tex]100\pi \, \text{cm}^2[/tex]
D. [tex]5\pi \, \text{cm}[/tex]



Answer :

To determine the exact area of a circle with a diameter of 10 cm, we follow these steps:

1. Determine the radius of the circle:
- The radius is half of the diameter. Given the diameter is 10 cm, the radius [tex]\( r \)[/tex] is:
[tex]\[ r = \frac{\text{diameter}}{2} = \frac{10 \text{ cm}}{2} = 5 \text{ cm} \][/tex]

2. Use the formula for the area of a circle:
- The area [tex]\( A \)[/tex] of a circle is given by the formula:
[tex]\[ A = \pi r^2 \][/tex]
- Substituting the radius into the formula:
[tex]\[ A = \pi (5 \text{ cm})^2 = \pi \times 25 \text{ cm}^2 = 25\pi \text{ cm}^2 \][/tex]

Therefore, the exact area of a circle with a diameter of 10 cm is [tex]\( 25\pi \text{ cm}^2 \)[/tex].

The correct option is:
25π cm²