Answer:
Step-by-step explanation:
<u>Sum of n terms formula:</u>
<u>Solving for n</u>
- 3480 = 1/2n(9 + 165)
- 3480 = 87n
- n = 3480/87
- n = 40
The total angle sum of a triangle is 180°
As such, 180= 78 + 2s +4s
102= 6s
s=17
To the nearest inch it'll be
d×3.14=63
= 20 inches
