Question

If angle ACB is a right angle, m angle 1 = 4y, and m angle 2 = 2y + 18, find m angle 2.

Here's what I did.
4y = 2y + 18
-2y on both sides
2y/2 = 18/2
y = 9

2y + 18
2(9) + 18
18 + 18
angle 2 = 36 degrees.

They say that the correct answer is 42 degrees. What did I do wrong?

Answer 1

What are angles 1 and 2? There's not enough information here to help.

Answer 2

angle 1 is 4y
angle 2 is 2y + 18

Answer 3

They wanted me to find angle 2.

Answer 4

Your first step is the error... you set angle 1 equal to angle 2, but this doesn't have to be the case.

Answer 5

angle 1 PLUS angle 2 + right angle = 180
so
angle 1 PLUS angle 2 = 90

Then sub in the expressions and solve.

Answer 6

oh wait, it isn't a triangle... sorry

Answer 7

It's alright.

Answer 8

angle 1 + angle 2 = 90 because it's a right angle overall

Answer 9

Is it like this?

Answer 10

They didn't show a picture of it. They just stated what I said in the original question.

Answer 11

Ok, well it's hard without knowing specifically where angles 1 and 2 are, but my guess (hate to guess...) is that they mean you split the right angle into angle 1 and angle 2

Answer 12

So: 4y + 2y + 18 = 90
6y = 72
y = 12

m angle 1 = 4y = 4(12) = 48
m angle 2 = 2y + 18 = 2(12) + 18 = 42

Check: 42+48 = 90

Answer 13

Thanks! I worked it out as well, and came out with the same answer as you. I understand now. :)

Answer 14

Glad to help...

Answer 15

I think this statement from the problem may be a typo: If angle ACB is a right angle,
Should it state that Triangle ACB is a right triangle with acute angles 1 and 2?

Answer 16

I still don't understand what angles 1 and 2 are... this problem is not very descriptive.

Answer 17

Interestingly, it doesn't change the outcome :)

Answer 18

@Directrix that was what I was thinking but I wasn't too sure

Answer 19

Or...