Question

Please help don't know how to do

Answer 1

Area of a triangle is (basexheight)/2

That's what your Formula, then you have to plug in the numbers

so the algebraric expression is (5xn)/2

For then end if you look at the patteren for the height it goes by 2. So the last height would be 10.
Plug that into the equation, which would be (5x10)/2=25