Answer:
885.18
Step-by-step explanation:
Base = 18x18=324
triangles = 1/2(18)height
To find the height, you could divide it in half and use the 30-60-90 rule or Pythagorean theorem.
9²+b²=18²
81+b²=324
b²=324-81
b²=243
b=√243
b=15.58
So each triangle is 1/2(18)(15.58845)=140.2961.
Four of them would be 561.1845.
Now add the base.
561.1845+324=885.1844
