Pentagon A, rectangle B and triangle C formed the figure below. The ratio of the area of A : B : C is 6 : 5 : 3. If \( {1 \over 4}\)of C is shaded, what fraction of the figure is unshaded? The figure is not drawn to scale.
A : B : C = 6 : 5 : 3
(area of Pentagon)/(area of Triangle) = 6/3 = 2 = A/C
shaded = 1/4c
unshaded = area of Pentagon - shaded
= 2c - 1/4c
= (8c - c)/4
unshaded = 7/4c = 7/4 * A/2
unshaded = 7/8 (area of Pentagon).
unshaded = 7/8 (area of figure)
7/8
