To find the amount of fabric for one side of the purse you will find the area of the trapezoidal space that is created. The latch is on the top, so the 2 in is not necessary information.
A = 1/2 h(b1 + b2) 1/2 x 13 x (10 + 16) A = 169 square inches of fabric will be needed.
The angles diagonally opposite each other are congruent while those adjacent to each other add up to 180 degrees. You can get eight congruent angles with a transversal if the two lines are parallel, because each angle would be 90.