Calculate the circumference of circles given their radius or diameter.

Hey evenesschristopher61, good to see you again. Here are the solutions to the problems: 1. Calculate the circumference of the circles below: a) Radius r = 7 cm Step 1: Use the formula for circumference C = 2 r. C = 2 × (22)/(7) × 7 cm Step 2: Simplify the expression. C = 2 × 22 cm C = 44 cm The circumference is 44 cm. b) Diameter d = 21 cm Step 1: Use the formula for circumference C = d. C = (22)/(7) × 21 cm Step 2: Simplify the expression. C = 22 × 3 cm C = 66 cm The circumference is 66 cm. c) Diameter d = 4 cm Step 1: Use the formula for circumference C = d. C = (22)/(7) × 4 cm Step 2: Simplify the expression. C = (88)/(7) cm The circumference is (88)/(7) cm or approximately 12.57 cm. 2. Calculate the circumference of a circle whose: a) radius is 9 cm Step 1: Use the formula for circumference C = 2 r. C = 2 × (22)/(7) × 9 cm Step 2: Simplify the expression. C = (44 × 9)/(7) cm C = (396)/(7) cm The circumference is (396)/(7) cm or approximately 56.57 cm. b) diameter is 3.5 m Step 1: Use the formula for circumference C = d. C = (22)/(7) × 3.5 m Step 2: Convert 3.5 to a fraction and simplify. C = (22)/(7) × (7)/(2) m C = 11 m The circumference is 11 m. 3. A circular garden is 21 m in diameter. Find the length of wire required to fence the garden. Step 1: The length of wire required is equal to the circumference of the garden. Use the formula C = d. C = (22)/(7) × 21 m Step 2: Simplify the expression. C = 22 × 3 m C = 66 m The length of wire required is 66 m. 4. The length of a minute hand of a clock is 12cm. Find the distance that the tip of the minute hand moves in 60 minutes. (Take = 3.14). Step 1: In 60 minutes, the minute hand completes one full revolution. The distance moved by the tip is the circumference of the circle traced by the minute hand. The length of the minute hand is the radius r = 12 cm. Use the formula C = 2 r. C = 2 × 3.14 × 12 cm Step 2: Multiply the values. C = 24 × 3.14 cm C = 75.36 cm The distance the tip moves is 75.36 cm. 5. If the circumference of a circle is 154cm. Find its radius. Step 1: Use the formula for circumference C = 2 r. 154 cm = 2 × (22)/(7) × r Step 2: Simplify the right side. 154 cm = (44)/(7) r Step 3: Solve for r. r = (154 × 7)/(44) cm r = (1078)/(44) cm r = 24.5 cm The radius is 24.5 cm. 6. Find the diameter of a circle whose circumference is 66cm. Step 1: Use the formula for circumference C = d. 66 cm = (22)/(7) × d Step 2: Solve for d. d = (66 × 7)/(22) cm Step 3: Simplify the expression. d = 3 × 7 cm d = 21 cm The diameter is 21 cm. Send me the next one 📸