Answer:
50π cm²
Step-by-step explanation:
In this case we have that the area of the boomerang has been the area of the largest semicircle minus the area of the smaller semicircles.
We know that the radius is half the diameter:
r = d / 2 = 20/2
r = 10
Now we have to:
Alargest = π · r²
Alargest = π · (10 cm) ²
Alargest = 100π cm²
Asmaller = π · r²
Asmaller = π · (5 cm) ²
Asmaller = 25π cm²
Finally, the boomerang area has been:
Aboomerang = 100π cm² - 2 · (25π cm²)
Aboomerang = 50π cm²
