Which set of values could be the side lengths of a 30-60-90 triangle? O A. {6,613, 12)
O B. {6, 12, 12.3}
O C. {6,6.12, 12}
O D. {6, 12, 12/3)

I think :

c is 30 triangle

b is 60 triangle

d is 90 triangle

We are given

The order of the letter sequence is important. The letters pair up based on how they are arranged. We see that A and E are the first letters of the sequences. So this means that angles A and E are the same measure

angle A = angle E

3x+20 = 5x-80

3x-5x = -80-20

-2x = -100

x = -100/(-2)

x = 50

Use this x value to find the measure of angle A

angle A = 3x+20

angle A = 3(50)+20

angle A = 150+20

angle A = 170 degrees