Answer:
r = 4
General Formulas and Concepts:
<u>Pre-Alg</u>
- Order of Operations: BPEMDAS
- Equality Properties
Step-by-step explanation:
<u>Step 1: Define equation</u>
-5 + 22 = r - 4 + 3r + 5
<u>Step 2: Solve for </u><em><u>r</u></em>
- Combine like terms: 17 = 4r + 1
- Subtract 1 on both sides: 16 = 4r
- Divide 4 on both sides: 4 = r
- Rewrite: r = 4
<u>Step 3: Check</u>
<em>Plug in r to verify it's a solution.</em>
- Substitute: -5 + 22 = 4 - 4 + 3(4) + 5
- Add/Subtract: 17 = 3(4) + 5
- Multiply: 17 = 12 + 5
- Add: 17 = 17
∠1 and ∠2 are alternate exterior angles where transversal BE crosses parallel lines AC and DF, therefore they are equal. ∠2 and ∠3 are opposite angles of a parallelogram, therefore they are equal.
... ∠1 = ∠2
... 3x -5 = 2x +15 . . . . substitute the given values
... x = 20 . . . . . . . . . . . add 5-2x
The measures of angles 1, 2, and 3 are 2·20+15 = 55 . . . degrees.
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