First, you need to multiply each of these numbers. This is a rectangle so you would do l*w, l*h, and h*w. You would do all of these things and then multiply each expression by 2 to complete the equation. Then add all of them together and you have your answer. The reason you multiply by two is because there are 2 versions of this for each equation. The top and bottom, the two vertical sides, and the two horizontal sides. 7.5*4.5*2=67.5, 7.5*3.25*2=48.75, and 4.5*3.25=29.25. Now add. 67.5+48.75+29.25=145.5 as our grand total.
When the sides are the same then the triangles are congruent. because they all have exactly the same sides. because the two triangles do not have exactly the same sides.
