The circumference of a semicircle is 15.42 cm. What is the area of the semicircle?

The circumference of a semicircle is 15.42 cm. What is the area of the semicircle?

The circumference of a semicircle = half of the circumference of the original circle + a diameter
Therefore, the radius is 15.42 (3.14 + 2) = 3cm
The semicircle area is 3.14 × 3 × 3 × 1 / 2 = 14.13 square centimeter

The circumference of a quarter circle is 14.28cm. What is its area in square centimeter

The circumference of the circle is 14.28 × 4 = 57.12cm;
The radius of the circle is 57.12 △ (2 × 3.14) ≈ 9.1cm;
The area of the circle is 3.14 × 9.1 ^ 2 ≈ 260cm ^ 2 ^2 is the square
A: the area of a circle is 260 square centimeters