Practice Radians in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

A radian is an angle measurement defined by the arc length it subtends on a unit circle: one radian is the angle at which the arc length equals the radius. A full circle is 2Ο€2\pi radians (about 6.28 radians), making radians the natural unit for trigonometry and calculus.

It ties angle directly to the circle’s geometry instead of degree counting.

Showing a random 20 of 50 problems.

Example 1

medium
Convert 3Ο€4\frac{3\pi}{4} radians to degrees.

Example 2

challenge
Show that for small ΞΈ\theta in radians, sinβ‘ΞΈβ‰ˆΞΈ\sin\theta \approx \theta. Use it to estimate sin⁑(0.05)\sin(0.05).

Example 3

hard
Find the area of a sector with radius 1212 cm and arc length 99 cm.

Example 4

easy
Convert 270∘270^\circ to radians.

Example 5

medium
A central angle of Ο€2\frac{\pi}{2} radians subtends an arc of length 55 cm. What is the radius?

Example 6

easy
Convert Ο€3\frac{\pi}{3} radians to degrees.

Example 7

easy
In a unit circle, what arc length is subtended by an angle of Ο€/4\pi/4 radians?

Example 8

easy
Approximately how many degrees is 11 radian?

Example 9

challenge
On a circle of radius rr, an inscribed angle subtends an arc of length Ο€r/3\pi r / 3. Find the inscribed angle in radians.

Example 10

medium
A pendulum swings through an arc of 0.80.8 m on a string of length 22 m. Find the angle swept in radians.

Example 11

hard
Compute the linear speed at the equator due to Earth's rotation if Earth's radius is 63786378 km and it rotates once every 2424 hours.

Example 12

hard
Find tan⁑(5Ο€6)\tan\left(\frac{5\pi}{6}\right).

Example 13

easy
Convert 360Β°360Β° to radians.

Example 14

medium
Convert 7Ο€4\frac{7\pi}{4} radians to degrees and identify which quadrant this angle is in.

Example 15

medium
Find the area of a sector with radius 44 and central angle Ο€2\frac{\pi}{2}.

Example 16

hard
A wheel of radius 3030 cm rotates at 120120 rpm (revolutions per minute). Find the angular velocity in radians per second and the linear speed of a point on the rim.

Example 17

medium
Express βˆ’Ο€3-\frac{\pi}{3} as a positive coterminal angle in [0,2Ο€)[0,2\pi).

Example 18

easy
Convert Ο€\pi radians to degrees.

Example 19

easy
Convert 60∘60^\circ to radians.

Example 20

medium
A wheel turns through 4Ο€4\pi radians. How many full revolutions is that?