Trick triangles

[BIG T]

A black triangle has a base length of x. It is known that when the lenth of the base has 1 added and is then doubled this is the same as the height of the triangle.

A small white triangle has an area of 9-x. It is placed in the middle of the black triangle. A red triangle is then made with the same area of the black left showing. The red triangle has an base length of x-3 find its hieght

[zaza]

Area of a triangle is 1/2 base x height.

Try thinking about the question and then tell us your thoughts.

[Shaggy Hiker]

It's a nice little problem. Each of the pieces can be turned into a simple little equation. You then end up with about three equations, all based off of x, h, and the formula zaza mentioned. Unfortunately, this could hardly look more like homework, so I doubt you will find anyone on here who will give you the answer. However, if you were to show work on each or any of the equations, we'd be able to talk about it more directly.

For instance, finding the area of the black triangle based only on the first statement is not definitively possible, but you can find the area as a function of x using that statement and the formula zaza mentioned. That function of x will be of some value in figuring out the final answer.

[BIG T]

well i got that the area of the black triangle is xsquared +x
and the only thing i don't no is if you do the next equation like that (x2+x)-(9-x) or just like x2+x-9-x

[BIG T]

to find the area left of the black triangle

[opus]

You have the area of the BlackTriangle (x^2 + x)
The area of White Triangle is given (9 - x)
So the area of the Red Triangle is (x^2+x-(9-x)), you have an mistake in your second equation for that, if there is a "-" in fromt of the bracket and you want to delete it, you have to switch all "+" to "-" and vice versa in this bracket!

Area Red Triangle = (x^2+x-(9-x)) = (x^2 +x-9+x)=x^2+2x-9!!

[BIG T]

Thnx mate