2. Ans. 506 yards. Find the circumference of a circle whose diameter is 17 ft. 6 in. 3. How many poles are there in the circumference of a circular plot of ground whose diameter is 42 yards? Ans. 24. 4. Find the expense of planting the circumference of a circular plot of ground whose diameter is 126 feet with quicks 1 yard apart at 1s. 6d. each. Ans. £9. 18s. 5. Find the diameter of a circle whose circumference To find the length of a circular arc. Multiply the circular measure by the radius of the circle. Ex. The arc of a circle whose radius is 4 ft. 8 in. subtends an angle of 75° 16′ 24′′ at the centre; find the length of the arc. 180° 648000", 75° 16′ 24′′ = 270984". = I. Find the length of a circular arc whose radius is 14 inches, and which contains 16°. Ans. 3 91. 2. Find the length of a circular arc whose radius is 3 ft. 6 in., and which contains an angle of 56°. 3. Ans. 3 ft. 5 in. Find the length of a circular arc whose radius is 20 ft. 9 in., and which contains an angle of 15° 9'. Ans. 5'488. 4. The length of a circular arc is 16 feet, and it contains 11° 15'; find the diameter. Ans. 168 feet. AREA OF CIRCLE. XIII. To find the area of a circle. Multiply the square of the diameter by 11, and divide by 14. Ex. I. Ex. 2. 9 ft. 4 in. Find the area of a circle whose diameter is 256. To find the diameter of a circle when the area is given. Multiply the area by 14 and divide by 11, and extract the square root. Ex. The area of a circle is 240. 7.6 square feet; find To find the area of a circular ring. Multiply the sum of the inner and outer diameters by their difference; then multiply by 11 and divide by 14. Ex. Find the area of a circular ring, whose inner and outer diameters are 12 and 20. To find the area of a circular sector. Multiply the circular measure of the angle subtended by the arc by the square of the radius, and divide by 2. Ex. Find the area of a circular sector whose radius is 28, and which contains an angle of 50° 36'. Circular Measure = '883 282=784 3532 7064 6181 2 692.272 346*136 Ans. |