Big Ideas Math Geometry, 2014
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Big Ideas Math Geometry, 2014 View details
5. Measuring and Constructing Angles
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Exercise 5 Page 39

We can find the measure of the angle by reading on the protractor's curved section.

m∠ MHK=90^(∘), right angle

Practice makes perfect

In the diagram, we can see six points, five rays, and a protractor.

For this exercise, we only need to consider three of the points, two of the rays, and the protractor. Let's remove the rest so that it is easier to view.

By looking at the numbers on the protractor's curved section, we can see that on the inner scale HM passes through 145^(∘) and HK through 55^(∘). According to the Protractor Postulate, the measure of ∠ MHK is equal to the absolute value of the difference between these two values. m∠ MHK = |145^(∘) - 55^(∘)| = 90^(∘) Now, we can classify the angle using its measure.

Type Measure
Acute 0^(∘)
Right m=90^(∘)
Obtuse 90^(∘)
Straight m=180^(∘)

Because our angle is 90^(∘), we know that it is a right angle.