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Find the measure of each angle

publish date1969/12/31 00:00:00 UTC

In the figure, find the measure of each angle of △ABC

B C A x 2x x + 32°

Correct Answer

(1) 37
(2) 69
(3) 74

Explanation

We will use the fact that the sum of the angle measures of any triangle is 180° to write an equation that models the situation. We can then solve the equation to find the unknown angle measure , and use it to evaluate the expression \(2x\) and \(x + 32^o\) 

  • The sum of the angle measures of any triangle is 180o
    • \(x + 32^o + x + 2x = 180^o\)
  • Combine like terms: x + x + 2x = 4x
    • \(4x + 32^o = 180^o\)
  • To isolate the variable term, 4x subtract 32o from both sides
    • \(4x + 32^o - \color{red}{32^o} = 180^o - \color{red}{32^o}\)
  • Do the subtraction
    • \(4x = 148^o\)
  • To isolate x, divide both sides by 4
    • \(\frac{4x}{\color{red}{4}} = \frac{148^o}{\color{red}{4}}\)
  • Do the division.  This is the measure of ∠B

Reference

Mathematics for college students


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