Question

Angle A is circumscribed about circle O. What is the measure of angle A?

Answer 1

Answer:

84°

Step-by-step explanation:

∠ COB = 2 × 48° = 96°

∠ ABO = ∠ ACO = 90°

From ABOC:

∠ CAB + 2×90° + 96° = 360°

∠ CAB = 360° - 276° = 84°

Answer 2

Find the angle of A.

So, $\angle COB=2\times\angle CDB$

$\angle COB=2\times 48$°

$\angle COB=96$°

In quadrilateral $COBA$

$\angle O+\angle A+\angle B+\angle C=360$°

$96$° $+\angle A+90$° $+90$° $=360$°

$\angle A=360$°$-90$°$-90$°$-96$°

$\angle A=84$°