The adjacent sides of a parallelogram measure 15 cm and 8 cm, and the perpendicular distance between the two sides of length 15 cm is 6 cm. What is its area in square cm?

The area of a parallelogram is base $x$ the height perpendicular to THAT base. Here the 6 cm height belongs to the 15 cm sides, so the area = $15\times 6=90$ sq cm. The trap $120=15\times 8$ multiplies the two adjacent sides, which is valid only for a rectangle; $48=8\times 6$ pairs the height with the wrong base; 45 halves the product as though the figure were a triangle.