The figure below is a diagram of a trapezoidal table that needs to be stained. each can of stain will cover 50 square inches.

Note that there are some useless information here. But all you need to know is that the area of a trapezium is the average of the 2 parallel bases multiplied by the height.

Area = (32 + 24) / 2 * 9 = 252

Since 5 cans of stain can only cover an area of 250, you will need 6 cans of stain.

to find the perimeter, you add up all the lengths of the sides. in this case you would have to add up 18+22+40+80 which equals 160.