There are three math problems and a composition that can't be done to find the shadow area. Can you teach me? Thank you.
(1) Shadow area = 6× 4÷ 2 = 12. (2) The figure is inaccurate, 6 is at the midpoint of 12, the upper right triangle is 4 and 8, the area of the white right triangle is = 1/4, and the shadow area is 3/4 ∴ shadow area = 12× 8/2× 3/4 = 36. (3) White shadow area = 7.5× 2 ÷ (10-8 )×10-7.5 = 75-7.5 = 67.5 square centimeters.