## gabbyalicorn one year ago Figure DEFG is equivalent to a trapezoid with a semicircle removed from its upper base. What is the area of figure DEFG?

1. gabbyalicorn
2. Michele_Laino

first step: we have to compute the area of trapezoid, which is: $Area = \frac{{\left( {B + b} \right) \times h}}{2} = \frac{{\left( {14 + 8} \right) \times 5}}{2} = ...c{m^2}$

3. gabbyalicorn

55

4. Michele_Laino

that's right!

5. Michele_Laino

second step: we have to compute the area of the half circle: $area = \pi \times 4 \times 4 = ...c{m^2}$ please don't multiply by 3.14

6. gabbyalicorn

XD okay

7. gabbyalicorn

i got 16

8. Michele_Laino

oops.. the area is: $area = \frac{{\pi \times 4 \times 4}}{2} = ...c{m^2}$

9. gabbyalicorn

8

10. Michele_Laino

yes! it is 8*pi

11. gabbyalicorn

B? :D

12. Michele_Laino

now the requested area is the subtraction between those areas, namely: ${\text{requested area}} = {\text{area of trapezoid - area of halfcircle}}$

13. Michele_Laino

hint: $\begin{gathered} {\text{requested area}} = {\text{area of trapezoid - area of halfcircle = }} \hfill \\ {\text{ = }}55 - 8\pi = ... \hfill \\ \end{gathered}$

14. gabbyalicorn

147.58 i think i didnt do it correctly

15. Michele_Laino

no, you don't have to multiply by 3.14, the right option is B as you wrote before

16. gabbyalicorn

but then whhy did u put the pi ;-;

17. Michele_Laino

because the area of the half circle is: 8*pi

18. gabbyalicorn

:I kay.

19. Michele_Laino

:)

20. gabbyalicorn

Thanks. :)

21. Michele_Laino

:)

22. gabbyalicorn

my face

23. gabbyalicorn

lol ^

24. Michele_Laino

25. gabbyalicorn

LOL. Well this time I didn't make it XDDDD but i'm glad you like it.

26. Michele_Laino

:)

27. gabbyalicorn

Now i can sleep :) thank you Z_Z