Question

Plz help me!!

I have no clue how to do this because my teacher moves to fast for me. If you can help out that would be really appreciated!!

Answer 1

1. x = 65

2. x = 40

3. x = -7

4. x = -4

5. x = -7

6. x = 4

Explanation:

Angles in a triangle always add up to 180 degrees.

Thus, for each triangle you can write an equation setting the sum of the three angles equal to 180, and solving for x.

1. 180 = 80 + 35 + x

180 - (80 + 35) = x

180 - 115 = x

65 = x

2. 180 = 70 + 70 + x

180 - (70 + 70) = x

180 - 140 = x

40 = x

3. 180 = 76 + 41 + (x+ 70)

180 - (76 + 41) = x + 70

180 - 117 = x + 70

63 = x + 70

63 - 70 = x

-7 = x

4. (the red square means its a right angle = 90 degrees)

180 = 90 + 25 + (x + 69)

180 - (90 + 25) = x + 69

180 - 115 = x + 69

65 = x + 69

65 - 69 = x

x = -4

5. 180 = 50 + (57 +x) + (x + 87)

180 - 50 = (57 +x) + (x + 87)

130 = (57 +x) + (x + 87)

combine like terms

130 = 144 + 2x

130 - 144 = 2x

-14 = 2x

-7 = x

6. 180 = 80 + (9x + 4) + (16x - 4)

180 - 80 = (9x + 4) + (16x - 4)

100 = (9x + 4) + (16x - 4)

combine like terms

100 = 25x + 0

100 = 25x

4 = x