The measure of arc QR in the circle is
To find the measure of arc QR in circle O, given that PQ is a tangent and PRT is a secant, we can use the properties of circles and their angles:
1. The angle formed by a tangent and a secant is equal to half the difference of the measures of the intercepted arcs. In other words, the angle outside the circle angle P is equal to
.
2. We are given:
-
3. The formula relating the angle and arcs is:
4. Plugging in the known values, we get:
5. To solve for
, we multiply both sides by 2 and then add
to both sides:
6. Calculate the result to find
arc QR =