Question

The angle of measures ${72}^{\circ }$ and ${144}^{\circ }$ are bisected to get 'a' and 'b' respectively.
What is the value of a+b in degrees?

• A. 7.0 cm
• B. 6.5 cm
• C. 10.0 cm
• D. 5.0 cm

Answer 1

The correct option is B

6.5 cm

An angle bisector bisect the given angle into two smaller equal angles.
Therefore,
$a=\frac{72}{2}={36}^{\circ }$
$b=\frac{144}{2}={72}^{\circ }$
$a+b=72+36={108}^{\circ }$