Open in App
Log In Start studying!

Select your language

Suggested languages for you:

Problem 330

If two chords of a circle subtend different acute inscribed angles, the smaller angle belongs to the shorter chord. Prove the statement and its converse.

Short Answer

Expert verified
The proof has two parts: 1. For the given statement: If two chords of a circle subtend different acute inscribed angles, the smaller angle belongs to the shorter chord, use the inscribed angle theorem to find measures of arcs AB and CD. Since ∠ACB < ∠ADB, we get m(arc AB) < m(arc CD). The length of a chord is proportional to the length of its intercepted arc, so AB < CD. 2. For the converse: If AB < CD, then using the properties of chords and arcs, we have m(arc AB) < m(arc CD). Using the inscribed angle theorem, we get ∠ACB < ∠ADB. This completes the proof of the statement and its converse.
See the step by step solution

Step by step solution

Unlock all solutions

Get unlimited access to millions of textbook solutions with Vaia Premium

Over 22 million students worldwide already upgrade their learning with Vaia!

Step 1: Diagram

Draw a circle with center O. Let AB and CD be two distinct chords of the circle. Let ∠ACB and ∠ADB be different acute inscribed angles such that ∠ACB < ∠ADB.

Step 1: Prove Smaller Angle Belongs to Shorter Chord

We need to show that if ∠ACB < ∠ADB, then AB < CD. To prove this, we will first find the measures of the arcs AB and CD using the inscribed angle theorem. The inscribed angle theorem states that the measure of an inscribed angle is half the measure of its intercepted arc. Therefore, we have: m(arc AB) = 2∠ACB and m(arc CD) = 2∠ADB Since ∠ACB < ∠ADB, we know: m(arc AB) < m(arc CD) Now, we'll use the fact that the length of a chord is proportional to the length of its intercepted arc. Thus, if m(arc AB) < m(arc CD), then AB < CD. This proves the first part of the statement.

Step 2: Prove the Converse

Now, we need to show that if AB < CD, then ∠ACB < ∠ADB. If AB < CD, then by the same properties of chords and arcs that we used in Step 1, we know that: m(arc AB) < m(arc CD) Using the inscribed angle theorem again, we have: 2∠ACB = m(arc AB) and 2∠ADB = m(arc CD) Since m(arc AB) < m(arc CD), we know: 2∠ACB < 2∠ADB Divide both sides by 2 to get: ∠ACB < ∠ADB This proves the converse of the statement, completing the solution.

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Access millions of textbook solutions in one place

  • Access over 3 million high quality textbook solutions
  • Access our popular flashcard, quiz, mock-exam and notes features
  • Access our smart AI features to upgrade your learning
Get Vaia Premium now
Access millions of textbook solutions in one place

Join over 22 million students in learning with our Vaia App

The first learning app that truly has everything you need to ace your exams in one place.

  • Flashcards & Quizzes
  • AI Study Assistant
  • Smart Note-Taking
  • Mock-Exams
  • Study Planner
Join over 22 million students in learning with our Vaia App Join over 22 million students in learning with our Vaia App

Recommended explanations on Math Textbooks