Question

In circle "R" below, determine the length of arc AB if BR = 5 units.
A. 31.4 units
B. 15.7 units
C. 11.775 units
D. 3.925 units

Answer 1

$l=2 \pi r( \frac{degrees}{360} )$

$l=2 \pi$ × 5 × $\frac{135}{360}$ = 11.78

Answer 2

See the pic, I'd solved in it.