Hi Ann.

Let h = the height of the triangle and b = the length of the base and A
= the area. I'm sure you know the relationship:

A = (1/2) b h

Now look at your problem:

"The height of a triangle is 4cm less than the base. "

That means h + 4 = b.

"The area is 198cm²."

That means A = 198.

"Find the height"

is asking you to calculate h.

So from the relationship A = (1/2) b h, we should try to replace all the
variables (letters) except h, then solve for h. So just substitute:

A = (1/2) b h
(192) = (1/2) (h + 4) h

Try simplifying this and then solve for h and you are done!

Hope this helps,
Stephen La Rocque.