1.A pie is circular in shape. One slice of the pie has an area of 5 in2 and a radius of 5 in. Find the central angle for this slice of pie in radians, rounded to the nearest tenth.

Question

-0.4 radians
-0.1 radians
-2.5 radians
-2.0 radians
2.For a particular circle and a sector of the circle, Albert estimates that the area of the sector is around one-fourth or one-fifth of the area of the whole circle. Which of the following are possible measures for the central angle? Select the two correct answers.
-2π/3
-π/5
-π/2
-2π/5
-π/6

Answer 1

area of whole circle = pi r^2 = 25 pi
we have 1/5 of that circle which is 2 pi radians around
2 pi /5 = 0.4 pi
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2 pi / 4 = pi / 2
or
2 pi / 5

Answer 2

#1. A = 1/2 r^2 θ
#2. 1/4 or 1/5 of 2π