Answer:
Below in bold
Explanation:
b = 40.
d = 70
From the diagram:
a = c (because they are both opposite the equal angles), so:
2a + 2c + 2*40 + 2*70 = 360
But a = c so:
2a + 2a + 80 + 140 = 360
4a + 80 + 140 = 360
4a = 360 - 220 = 140
a = 35
so c = 35.