Find angle A if measurement of arc mDE is equal to 70° and measurement of arc mBC is equal to 12°.

Angle A = 29°

Step-by-step explanation:

Remember one thing that when two secants intersect in the exterior of a circle then A=1/2 (mDE-mBC) it means that the measure of the angle formed is one half the difference of the measures of the intercepted arcs

Now put the values in the equation.

A=1/2 (mDE-mBC)

A=1/2 (70-12)

A=1/2 (58)

A = 29°

Thus angle A = 29° ...