Question

Can someone please explain this to me?http://prntscr.com/azyvnf

Answer 1

You don't know the base nor the height of the triangle ok?

Answer 2

Okay?

Answer 3

So, suppose we call the base as x. How can we write the height?

Answer 4

You know that the height has 5 meter less than the base, so we can write this :
\[x-5\]Ok?

Answer 5

Yes

Answer 6

So now, you have
base = x
height = x-5
The area of the triangle is this formula,
\[A=\frac{b\cdot h}{2}\]Ok?

Answer 7

And you know that the area A is A=42, ok?

Answer 8

Okay.

Answer 9

So we can write the following equation,
\[42=\frac{x(x-5)}{2}\] This is the equation you should solve for x.

Answer 10

Ok

Answer 11

And 12m is the answer?

Answer 12

Yes!

Answer 13

Thanks!

Answer 14

You're welcome.