Find the measure of the angle
Answer 1
Given a circle with center O, and two points A and B on the circumference of the circle, form the angle AOB. If the radius of the circle is 5 cm and the arc AB measures 8 cm, find the measure of the angle AOB in radians and degrees.
Step 1: Find the circumference of the circle using the formula:
$ C = 2 \pi r $
Step 2: Substitute the radius into the formula:
$ C = 2 \pi (5) = 10 \pi \text{ cm} $
Step 3: Find the fraction of the circumference that the arc AB represents:
$ \frac{8}{10\pi} = \frac{4}{5 \pi} $
Step 4: Multiply this fraction by the total measure of the circle in radians (2π):
$ \text{Angle in radians} = 2 \pi \times \frac{4}{5 \pi} = \frac{8}{5} \text{ radians} $
Step 5: To convert radians to degrees, use the fact that π radians = 180 degrees:
$ \text{Angle in degrees} = \frac{8}{5} \times \frac{180}{\pi} \approx 91.56° $
Answer 2
Consider the same circle with radius 5 cm, and arc length AB as 8 cm. We need to find the angle AOB in radians and degrees.
1. Calculate the circumference:
$ C = 2 pi r = 10 pi ext{ cm} $
2. The fraction of the circle’s circumference that arc AB represents:
$ frac{8}{10pi} approx 0.2546 $
3. Multiply this by 2π to find the angle in radians:
$ ext{Angle in radians} = 0.2546 imes 2pi approx 1.6 ext{ radians} $
4. Convert to degrees:
$ ext{Angle in degrees} = 1.6 imes frac{180}{pi} approx 91.66° $
Answer 3
For a circle with radius 5 cm and arc length 8 cm,
1. Circumference:
$ C = 2 pi r = 10 pi $
2. Arc length fraction:
$ frac{8}{10pi} = frac{4}{5 pi} $
3. Angle in radians:
$ frac{8}{5} $
4. Angle in degrees:
$ approx 91.56° $
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