Solution 1:

Since it is an isosceles triangle,
a + 5 = b + 7
a = b + 2
without any more data, 'a' and 'b' can have infinite number of values.

Solution 2:



Area of shaded region: [spoiler](2/3)(pi)(r^2)[/spoiler]

overlap area is broken down into 2 equilateral triangles and 4 lobes

The 120/360 * area will only give area of triangles and 2 lobes, no???


When calculating area of overlap don't you have to figure out area of equilateral triangle and subtract it from 1/6 A to get the area of the small lobe.

shaded area = area of circle - ( 2 small lobes + 120/360*a)