Lol, were are learning the same thing! Anyway, Your answer would be 292.5. It would be this answer because the dotted lines are actually pointing out what the height is and the area of a triangle equals 1/2bh(base x height divided by 2). So knowing this information, you would multiply 13 x 45 and get an answer of 585. Then you would divide it by 2. This leads you back to the original answer of 292.5. I hope I helped! :)