Question

In the diagram below what is the approximate length of the minor arc AB

Answer 1

B

Explanation:

The length of the minor arc = circumference × fraction of circle

arc AB = 2π × 10 ×
`(90)/(360)`

= 20π ×
`(1)/(4)` = 5π ≈ 15.7 cm → B

Answer 2

Minor arc AB length = 15.74 cm

Explanation:

We know that, circumference of circle = 2πr

where r is the radius.

so the formula simply reduces this by the ratio of the arc angle to a full angle (360).

Given that arc angle is 90°.

So, arc length is the one forth length of the whole circle.

Whole circle arc length (circumference) = 2πr

= 2*3.14*10 = 62.83 cm

Now calculate the arc AB length =
`(1)/(4)` circumference of circle.

Minor arc AB length =
`(62.83)/(4)`

Minor arc AB length = 15.74 cm