Answer: 540.4 mm squared
Explanation:
Since there are 5 triangles, we can find the area of each one and multiply it by 5:
(bh)/2 * 5
the base is 8 because in an isosceles triangle, you divide the bottom side by 2
(2*20)/2 * 5 =
20 * 5 =
100
We can add this to the base, 440.4, and get a result of 540.4