math
posted by Thomas .
A triangle has an area of 15 cm^2 and a base of 5 cm. If a circle is drawn with a diameter equal to the length of the triangle's height, what is the area of the circle ?
a. 6 pi cm^2
b. 9 pi cm^2
c. 12 pi cm^2
d. 18 pi cm^2
e. 36 pi cm^2
please answer and explain

since a = bh/2, we have
h = 2a/b = 2*15/5 = 6
for a circle, a = pi r^2 = 9pi