Question

3. Triangle JKL is shown below. Which of the following is not a true statement about
the angles in the triangle?
J 7X+2
A. The sum of 2J + ZK + ZL = 180°
B. The measure of ZJ is 65
L
4x + 7
C. The measure of ZK is 89
D. The measure of ZL is 43°
8x

Answer 1

Option A is true because the sum of angles in a triangle is 180, so we can rule that one out immediately.

We can solve for x for the other 3 options by setting up this equation:

7x+2 + 4x+7 + 8x = 180 | Simplify

19x + 9 = 180 | Subtract 9

19x = 171 | Divide by 19
x=9

Now we can substitute x into all the values:
<J = 7x+2 = 65
<L = 4x+7 = 43
<K = 8x = 72

Looking at the options again, we can see that A, B, and D are true, leaving C to be false.