12 answer: because sunlight is parallel, the quadrilateral on the ground is a parallelogram. According to the nature of parallelogram, its circumference is 2× (55+40) = 190 (cm). According to the nature of right triangle, the right angle side of 300 is half of the hypotenuse, and its area can be obtained as ×55×40= 1 100(cm2).

14 answer: the area of parallelogram AEPH is equal to the area of parallelogram PGCF. By using that △ABD and △CDB, △PHD and △DFP, △BEP and △GPB are equal respectively, it is concluded that the areas of parallelogram AEPH and parallelogram PGCF are equal.