Geometry and TrigonometryHardArc length from a central angle
Geometry and Trigonometry practice question
A circle has a circumference of 16 centimetres. What is the length, in centimetres, of an arc that subtends a central angle of 45°?
Answer: 2
45° is 45/360 = 1/8 of the full turn, so the arc is 1/8 of the circumference: 16/8 = 2.
Common wrong answers
- If you answered 4
- 4 uses 1/4 of the circumference, as if the angle were 90°.
- If you answered 8
- 8 is half the circumference (180°).
- If you answered 720
- 720 multiplies 16 by 45 without dividing by 360.
More Geometry and Trigonometry questions
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In a right triangle, one leg is 5 and the hypotenuse is 13. What is the length of the other leg? - Hard
A circle has a radius of 4. What is the length of an arc that subtends a central angle of 90°? - Hard
A circle is defined by the equation (x − 3)² + (y + 2)² = 25. What is the radius of the circle? - Hard
What is 135° expressed in radians? - Hard
What is the length of segment PT? - Hard
What is the measure, in degrees, of the central angle of this sector?
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