There are 4 triangles with base of 5 and height of 8.4
Area of triangle = 1/2 x base x height
Area of triangle = 1/2 x 5 x 8.4 = 21 m^2
Multiply by 4 = 21 x 4 = 84 m^2
Area of the base = length x width = 5 x 5 = 25 m^2
Total area = 84 + 25 = 109 m^2