Question

11. Determine the measure of the angles below.

Answer 1

Answer:

11 - 125 and 55

12 - supplementary

Step-by-step explanation:

5x+20+3x-8=180

step 1 combine like terms

8x+12=180

step 2 subtract 12 from each side

8x=168

step 3 divide each side by 8

x=21

then you just plug in 21 to each equation to find that angle 1 = 125 and angle 2=55

Answer 2

Problem 11

Answers:

• 5x+20 = 125
• 3x-8 = 55

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Explanation:

The two angles shown here form a linear pair. They supplementary so they add to 180.

(5x+20)+(3x-8) = 180

(5x+3x) + (20-8) = 180

8x+12 = 180

8x = 180-12

8x = 168

x = 168/8

x = 21

We then find the angles to be

5x+20 = 5*21+20 = 125

3x-8 = 3*21-8 = 55

Note how 125+55 = 180 to help confirm the answers

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Problem 12

Answer: B) Vertical angles

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Explanation:

Vertical angles are angles that form after intersecting two lines, and the angles are opposite one another. So one example of a vertical angle pairing would be angles 1 and 3. The other vertical angle pair of this diagram are angles 2 and 4. Vertical angles are always congruent to one another.

In this diagram, angles 1 and 4 are adjacent since they are next to each other. In other words, they share a common line (think of apartment neighbors sharing a common wall). Since they are adjacent angles, there is no way they are vertical angles.

Angles 1 and 4 are also supplementary since they form a straight line. They are a linear pair for very similar reasons. This allows us to rule out choices A, C and D.

Side note: the term "linear pair" means that the angles are adjacent and supplementary.