Question 1 is a triangle with the first and second points having identical y values so the base has a length of abs(2-(-5)) which is 7, the height is abs(3-(-3)) or 6. The formula for the area of a triangle is 1/2 Base*Height or 1/2(7*6) or 3*7 which is 21. A generalized way to find the area of any polygon is to draw a rectangle using the highest, lowest, most negative and most positive points and then use the area - all the triangles or rectangles on the outside. Problem 2 is a square with 2 identical triangles outside the shape. Problem 3 if you follow the above procedure and connect the two opposite sides you will see that you have four rectangles made up of identical triangles.