how to solve number 4

Find the first semicircle area
Area semicircle can be determined by dividing the full area of circle by 2.
The first semicircle radius is 5 cm
semicircle area = 1/2 circle area
semicircle area = 1/2 × π × r²
semicircle area = 1/2 × 3.14 × 5²
semicircle area = 1/2 × 3.14 × 25
semicircle area = 39.25 cm²

Find the second semicircle area
Because the dimension of the second semicircle is congruent to the first semicircle, they have similar area measurement, 39.25 cm².

Find the quarter circle area
The area of quarter circle can be determined by dividing the full area of a circle by 4.
q circle = 1/4 × area of circle
q circle = 1/4 × π × r²
q circle = 1/4 × 3.14 × 10²
q circle = 1/4 × 314
q circle = 78.5 cm²

To find the entire area, add the area above together
area = first semicircle + second semicircle + q circle
area = 39.25 + 39.25 + 78.5
area = 157

The area of shaded region is 157 cm²