Question

Does Anybody know this? Find the area of the shaded sector

Answer 1

Step-by-step explanation:

your teacher was very nice and warned you about the trap in the question.

so, really, what do we have to do ?

a full circle represents 360°.

the shaded sector is the full circle minus the white sector !

this is the same as directly calculating the shaded sector for 360-75 = 285°.

so, the area of a circle is

pi×r²

in our case

pi×20² = 400pi

the needed fraction of the whole circle is either

75/360, if we want to subtract it for the solution

or

285/360, if we want to calculate the solution directly.

both lead to the same result.

400pi×360/360 - 400pi×75/360 =

= 400pi × 285/360 = 10pi × 285/9 = 2850pi/9 =

= 316.6666666...pi ≈ 316.7pi