Answer:
B) 306°
Step-by-step explanation:
1. Pentagons have a sum of interior angles of 540°
2. Triangles have a sum of interior angles of 180°
3. Knowing that triangle EFA is isosceles, we know that
<FEA = *<FAE, so they are equal to: (180° - <F) /2 = (180° - 36°) / 2
= 144° / 2
= 72°
4. m<A + m<B + m<C + m<D + m<E = 540°
It is also given that **m<D = 90°,
so therefore m<A + m<B + m<C + m<E = 450°
5. Now to find a+b+c+d (m<a + m<b + m< c+ m<d),
m<a = m<E - 72° and m<d = m<A - 72°
This means that
m<a + m<b + m< c+ m<d = (m<A - 72°) + m<B + m<C + (m<E - 72°) = 450°
6. Finally,
m<a + m<b + m< c+ m<d = 450° - 72° - 72° = 306°
EXTRAS
* < is an angle symbol
** m<D means measure of angle D
