Answer:
The answer to your question is: 278 cm²
Explanation:
Data
base = 10 cm
height = 8.9 cm
Formula
Square area = l x l
Triangle area = (b x h) / 2
Process
Find the area of the square
A = 10 x 10 = 100 cm²
Find the area of the triangle
A = (10 x 8.9) / 2 = 44.5 cm²
But, there are 4 triangles so, 44.5 x 4 = 178 cm²
Total area = 100 + 178 = 278 cm²