Ineed on question 18. i would appreciate it; and you : )

Hello!

First, let's take a look at the two angles together. We can see that the two angles, when the measures are combined, add up to form a line, DEF. We can therefore see that the two angles DEG and GEF must add up to 180 degrees, as the measure of a line is 180 degrees.

Therefore, we can create our equation.

(7x - 3) + (12x - 7) = 180

Now, solve for x.

7x - 3 + 12x - 7 = 180

19x = 190

x = 10

Finally, substitute x into the angle measures to find the integer measurements.

Angle DEG: 7x - 3

7 * 10 - 3

70 - 3

67 degrees

Angle GEF: 12x - 7

12 * 10 - 7

120 - 7

113 degrees

Just to be sure, add up the angle measurements to make sure they equal 180. 67 + 113 = 180, which means we did our math correctly.

Hope this helps!

δabc ≅ δdcb by sas because

db ≅ ac . . given (side)

bc ≅ bc . . reflexive property (side)

∠dbc ≅ ∠ acb . . alternate interior angles where transversal bc crosses parallel lines bd and ac (included angle)