Math Problem Statement

Given a cyclic quadrilateral PQRS inscribed in a circle with angles: ∠QRS = 130°, find the angles ∠QPR (y°) and ∠RTS (x°).

Solution

In the image, we see a cyclic quadrilateral PQRSPQRS inscribed in a circle, and a few angles labeled. The following angles and relationships are important:

  • QPR=y\angle QPR = y^\circ
  • TSR=x\angle TSR = x^\circ
  • QRS=130\angle QRS = 130^\circ

Key properties:

  1. Cyclic Quadrilateral Property: Opposite angles in a cyclic quadrilateral are supplementary, i.e., they sum to 180180^\circ.

    • This means QPR+QRS=180\angle QPR + \angle QRS = 180^\circ.
    • Given QRS=130\angle QRS = 130^\circ, we can find yy using the equation: QPR+130=180\angle QPR + 130^\circ = 180^\circ y=50y^\circ = 50^\circ
  2. Angle in the Same Segment: Angles subtended by the same arc in a circle are equal. Since QRS\angle QRS and RTS\angle RTS are subtended by the same arc QSQS, we have: RTS=QRS=130\angle RTS = \angle QRS = 130^\circ Thus, x=130x^\circ = 130^\circ.

Summary:

  • y=50y = 50^\circ
  • x=130x = 130^\circ

Would you like more details or have any further questions?

Related Questions:

  1. What are the properties of angles in a cyclic quadrilateral?
  2. How do you find the angles subtended by the same arc?
  3. What is the importance of the supplementary angle rule in cyclic quadrilaterals?
  4. How does the inscribed angle theorem apply to this diagram?
  5. Can we use alternate methods to verify the values of xx and yy?

Tip:

Always look for symmetrical properties in cyclic quadrilaterals—they can simplify complex angle calculations!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Cyclic Quadrilateral
Supplementary Angles
Angles Subtended by the Same Arc

Formulas

∠QPR + ∠QRS = 180° (Opposite angles in a cyclic quadrilateral)
∠RTS = ∠QRS (Angles subtended by the same arc)

Theorems

Cyclic Quadrilateral Property (Opposite angles are supplementary)
Angle Subtended by the Same Arc Theorem

Suitable Grade Level

Grades 9-12