Math Problem Statement

Using the Inscribed Angle Theorem, find the values of the angles labeled 'a' and 'b' in the circle where angle PQS is 60° and angle SRT is 30°.

Solution

The image you provided shows a circle with inscribed angles, labeled using the Inscribed Angle Theorem. The important details from the diagram include:

  • PQS=60\angle PQS = 60^\circ
  • SRT=30\angle SRT = 30^\circ
  • There are two unknown angles labeled aa^\circ and bb^\circ.

Key Points:

  1. Inscribed Angle Theorem states that an inscribed angle is half of the measure of the intercepted arc. Thus, we can use this to determine the values of aa and bb.

  2. From the diagram:

    • PQS=60\angle PQS = 60^\circ is an inscribed angle. The intercepted arc of PQS\angle PQS is \overarcPS\overarc{PS}, which means the arc PSPS is 120120^\circ (since the inscribed angle is half of the arc).

    • Similarly, SRT=30\angle SRT = 30^\circ implies the intercepted arc \overarcQT\overarc{QT} is 6060^\circ.

  3. We can now determine:

    • Angle aa^\circ: Since the intercepted arc for angle aa is \overarcPT\overarc{PT}, which is the sum of arcs PSPS and QTQT, the arc PT=120+60=180PT = 120^\circ + 60^\circ = 180^\circ. Therefore, PRT=1802=90\angle PRT = \frac{180^\circ}{2} = 90^\circ, so a=90a = 90^\circ.

    • Angle bb^\circ: The angle bb intercepts the arc \overarcPR\overarc{PR}, which is 180180^\circ, so PRS=90\angle PRS = 90^\circ as well. Thus, b=90b = 90^\circ.

Summary:

  • a=90a = 90^\circ
  • b=90b = 90^\circ

Would you like further details on how the Inscribed Angle Theorem applies or any other clarification?

Related Questions:

  1. How does the Inscribed Angle Theorem relate to the central angle theorem?
  2. Can you calculate the arc length if the circle's radius is given?
  3. What is the difference between a central angle and an inscribed angle?
  4. How would the values of aa and bb change if the circle was larger but the angles remained the same?
  5. How can we use the Inscribed Angle Theorem to solve real-world problems involving circles?

Tip: Remember that the intercepted arc of an inscribed angle is always double the measure of the angle itself!

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Math Problem Analysis

Mathematical Concepts

Geometry
Circle Theorems
Inscribed Angle Theorem

Formulas

Inscribed Angle Theorem: Inscribed Angle = 1/2 * Intercepted Arc

Theorems

Inscribed Angle Theorem

Suitable Grade Level

Grades 9-12