Question

((MATHS FORM2 CHAPTER 5 CIRCLE)). HELPPPPPPPPPP I WILL MARK AS BRAINLIEST PLEASE SHOW YOUR WORKING :-)

Answer 1

Answer:

Step-by-step explanation:

strategy:  Find the area of the entire dartboard, then subtracted the inner circle from that whole.    we will have the entire outer circle,  so divide that by 2 for half of it.   Next divide the inner circle by 4 . Then add that to the outer circle answer from above.

whole circle = $\pi$*$20^{2}$ = 1257.142857 $cm^{2}$

inner circle = $\pi$*$10^{2}$ = 314.2857143 $cm^{2}$

1257.142857 - 314.2857143 = 942.8571427 outer circle

942.8571427 / 2 = 471.4285 ( half of the outer circle)

now find quarter of the inner circle

314.2857143 / 4 = 78.57142855

add the two parts together

78.57142855 + 471.4285  = 549.9999

The shaded regions = 550 $cm^{2}$