Math Problem Statement

In the adjoining figure, AOB is a straight line. Find ∠AOC and ∠BOD.

Solution

Let's solve this problem by focusing on the angles given in the figure.

  1. We are given that AOBAOB is a straight line, so the angles on the line sum to 180180^\circ.
  2. Angle AOC=x\angle AOC = x^\circ, and the other angles around point OO include:
    • 6565^\circ for COD\angle COD,
    • (2x20)(2x - 20)^\circ for BOD\angle BOD.

Step-by-step process:

  1. The angles AOC\angle AOC, COD\angle COD, and BOD\angle BOD are all adjacent, forming a straight line at AOBAOB. Thus, we have the equation:

x+65+(2x20)=180x + 65^\circ + (2x - 20^\circ) = 180^\circ

  1. Simplifying this equation: x+65+2x20=180x + 65 + 2x - 20 = 180 3x+45=1803x + 45 = 180 3x=1353x = 135 x=45x = 45^\circ

Now, we can find the required angles:

  • AOC=x=45\angle AOC = x = 45^\circ
  • BOD=2x20=2(45)20=9020=70\angle BOD = 2x - 20 = 2(45^\circ) - 20^\circ = 90^\circ - 20^\circ = 70^\circ

Final answers:

  • AOC=45\angle AOC = 45^\circ
  • BOD=70\angle BOD = 70^\circ

Would you like a deeper explanation of any part of this solution?

Here are five related questions you might find useful:

  1. What is the relationship between angles on a straight line?
  2. How do adjacent angles behave around a point?
  3. How can we apply algebraic techniques to solve angle problems like this?
  4. Can you think of other geometric situations where angles sum to 180 degrees?
  5. How would the problem change if AOBAOB wasn't a straight line?

Tip: Always check if angles form a linear pair or a full circle to simplify the calculation.

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Math Problem Analysis

Mathematical Concepts

Linear Pair of Angles
Angle Relationships

Formulas

Sum of angles on a straight line = 180°

Theorems

Linear Pair Theorem

Suitable Grade Level

Grades 8-10