I'm going to explain this a little more Maganda, because I want you to learn to understand it yourself.

Your math problem talks about all 3 angles of this triangle. The way they are described they are all related together. It says the largest angle is 5 times as big as the smallest. So, you know that if the smallest is **X **degrees, the largest is **5 times X** degrees. Then they talk about the 3rd angle. It is 18 degrees *less than *the largest angle. We already said the largest one is 5X degrees (5 times X). So, the third one is **5X - 18** degrees.

So, the three angles are:

X, 5X, and (5X-18)

At the beginning of the problem, it says that if you add all 3 angles together the sum is 180 degrees. So,

X + 5X + (5X - 18) = 180

Since this whole equation is + and -, you can ignore the ( ).

X + 5X + 5X - 18 = 180

put all the Xs together and you get 11X - 18 = 180

You want to get the X all by itself, so you need to do things to BOTH sides of the equation until X is alone.

First, add 18 to both sides:

11X - 18 **+ 18** = 180 **+ 18**

- 18 + 18 = 0, so

11X = 198

Now you can divide both sides by 11 to get X alone:

11X divided by 11 = X

198 divided by 11 = 18

so, X = 18

Now you can find out how big each of the 3 angles is, because you know how much X is.

Remember, the 3 angles are X, 5X and (5X-18)

Since X = 18, we know that the angles are

X = 18

5X = 90

5X-18 = 90 - 18 = 72

We can check the answer to make sure it all adds to 180

18 + 90 + 72 = 180?

YES

Let X = the measure of the smallest angle. Then the largest angle is 5X, and the remaining angle is 5X-18. So......

X + 5X + (5X-18) = 180

11X-18 = 180

11X=198

X=198/11

Then X=18 degrees. I'll leave it to you to figure out what that makes the other 2 angles (remember that one is 5X and one is 5X-18)