Geometry- calculating the area of the following shapes. explain.

1. 
area of big rectangle = 12 x 15 = 180
area of triangle = 1/2 (6)(4) = 12

Area of figure = 180 - 2(12) = 156 m^2

2.

Area of rectangle = 13 x 18 = 234
Area of semi-circle = 1/2 pi r^2= 254.47 / 2 = 127.235

Area of figure = 234 + 127.235 = 364.235 m^2

Hello!
volume of sphere =4/3.pi.r^3