The length of the hypotenuse of a 30, 60, 90 triangle is 7 how do you find perimeter?

It's almost good. You probably just forgot to divide by the common denominator 2.

The answer should therefore be
(21+7sqrt(3))/2
=21/2 + (7/2)sqrt(3)

@aiko are you sure these are right? i dont want to fail i solved half of them on my own to be safe...

Sorry, but I still don't get it

Fact: all 30-60-90 triangles are similar.

Fact: therefore the ratio of the perimeter to the hypotenuse is the same for all 30-60-90 triangles.

We have arbitrarily created a 30-60-90 triangle with hypotenuse = 2.

So to get a triangle with a hypotenuse of 7, we need to multiply everything by 7/2=3.5.
The sides of the given triangle is therefore (1,√3,2)×3.5, or
(3.5, 3.5√3, 7)
Add up the three numbers (lengths of sides) to get the perimeter.

I guess I'm lost my answer choices are;

7/2+21/2sqrt3
21+7sqrt3
7+21sqrt3
21/2+7/2sqrt3
So I don't understand

Does anyone have all the correct answers because the guy above has a handful of correct ones?

Did you add the three sides, 3.5, 3.5√3 and 7?

Remember that 3.5 is the same as 7/2, and so on.

That's the problem I don't know how to add them, I'm assuming It would be 21+7sqrt3

I did thanks for reminding me

plus when i first took it i left since id didn't finish and when i came back the question had different numbers before it was 5.2 then it became 4,7 w/ different answer choice...