Question

Which formula would be used to find the measure of angle 1

Answer 1

Option (4)

Explanation:

By the Angle of intersecting secants,

"If two lines intersect outside a circle, then the measure of the angle between these lines or secants will be one half of the difference between the intercepted arcs."

From the picture attached,

Angle between the secants = ∠1

Measure of intercepted arcs are a° and b°.

By this theorem,

m∠1 =
`(1)/(2)(a-b)`

Option (4) will be the answer.