Question

Find the length of a 90° arc of a circle with a diameter of 10 m​

Answer 1

7.85 m (3 significant figures)

Explanation:

Formula: arc length =
`2\pi r((\theta)/(360) )`

The radius of a circle is half the diameter, so r = 10 ÷ 2 = 5

Therefore, arc length = 2 x
`\pi` x 5 x
`((90)/(360) )`

=
`(5)/(2)\pi`

= 7.853981634...

= 7.85 m (3 significant figures)