SOLUTION: Please help! Suppose circle B, with a radius of 5 inches, has an angle ABC in standard position. Find the radian measure of the angle ABC with arc AB measuring 20 inches. Round

Algebra ->  Trigonometry-basics -> SOLUTION: Please help! Suppose circle B, with a radius of 5 inches, has an angle ABC in standard position. Find the radian measure of the angle ABC with arc AB measuring 20 inches. Round       Log On


   

Question 769013: Please help!
Suppose circle B, with a radius of 5 inches, has an angle ABC in standard position. Find the radian measure of the angle ABC with arc AB measuring 20 inches. Round to the nearest hundredth using 3.14 for pi.
my choices;
4
5
none
20
15
DESPERATE FOR HELP!!! thank you!!1
Found 3 solutions by Alan3354, MathLover1, rothauserc:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Suppose circle B, with a radius of 5 inches, has an angle ABC in standard position. Find the radian measure of the angle ABC with arc AB measuring 20 inches. Round to the nearest hundredth using 3.14 for pi.
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arc = r*angle
20 = 5*angle
angle = 4 radians.
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It couldn't be much simpler.

Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
The length of the arc is
2+pi%2Ar%2A%28A%2F%282+pi%29%29+=+r%2AA, if A is in radians and r is the radius of the circle,
given:
r=5in
r%2AA=20in.....substitute r
A=20in%2F5in
A=4

Answer by rothauserc(4718) About Me  (Show Source):
You can put this solution on YOUR website!
Use the formula S = r*theta
so theta = S / r = 20 / 5 = 4 radians