wikiHow Practice Problems to Find Arc Length 1. Arc of 120° in a circle with radius 8, find length. 2. Circle with diameter 12, arc of 30° length. 3. Circle of radius 5, arc length of 150°. 4. Circle of diameter 10, arc of 60° length. 5. Arc of 90° in circle of radius 7, find length. 6. Circle with radius 6, arc length of 240°. 7. Circle of diameter 14, arc of 45° length. 8. Arc of 180° in circle of radius 4, find length. 9. Circle of radius 9, arc length of 300°. 10. Circle of diameter 8, arc length of 120°. Note: The formulas used to find the length of an arc are as follows: Arc Length = (θ/360) * 2π * r, where θ is the degree of the arc and r is the radius of the circle. Answer key: 1. Arc of 120° in a circle with radius 8, length = 19.63 cm. 2. Circle with diameter 12, arc of 30° length = 3 cm. 3. Circle of radius 5, arc length of 150° = 26.18 cm. 4. Circle of diameter 10, arc of 60° length = 15.71 cm. 5. Arc of 90° in circle of radius 7, length = 12.57 cm. 6. Circle with radius 6, arc length of 240° = 43.98 cm. 7. Circle of diameter 14, arc of 45° length = 7 cm. 8. Arc of 180° in circle of radius 4, length = 25.13 cm. 9. Circle of radius 9, arc length of 300° = 52.36 cm. 10. Circle of diameter 8, arc length of 120° = 9.42 cm. Page