The remote angles theorem states that when one extends a side of a triangle, the angle formed between the extension and one of the sides of the triangle is equal to the sum of the two non-adjacent angles inside the triangle. One can apply this theorem here and state the following,
<BAC + <ABC = <ACD
Substitute,
(5y + 3) + (4y + 8) = (146)
Simplify,
9y + 11 = 146
Inverse operations,
9y + 11 = 146
-11 -11
9y = 135
/9 /9
y = 15
Now substitute this value back into the expressions to find the numerical measurement of (<BAC) and (<ABC),
