The figure is not drawn to scale. Three pentagons B, C and D are arranged as shown in the figure. The area of Pentagon B is ²₅ the area of Pentagon C. The area of Pentagon C is ²₅ the area of Pentagon D.
(a) Find the ratio of the area of Pentagon B to the area of Pentagon D.
(b) ³₄ of Pentagon B is shaded. What fraction of the whole figure is not shaded?

B	C	D
2x2	5x2
	2x5	5x5
4 u	10 u	25 u

(a)
Area of Pentagon C is the repeated identity. Make the area of Pentagon C the same. LCM of 5 and 2 is 10.

Pentagon B : Pentagon D
4 : 25

(b)
Shaded part of Pentagon B
= ³₄ x 4 u
= 3 u

Unshaded part of Pentagon B
= 4 u - 3 u
= 1 u

Unshaded part of Pentagon D
= 25 u - 3 u
= 22 u

Total figure unshaded
= 22 u + 1 u
= 23 u

Total figure
= 25 u + 1 u
= 26 u

Fraction of the whole figure that is unshaded
= ²³₂₆

Answer(s): (a) 4 : 25; (b) ²³₂₆