in a rectangular coordinate system , what is the area of a rhombus whose vertices have the coordinates ( 0 , 3.5 ) , ( 8 , 0 ) , ( 0 , - 3.5 ) , ( - 8 , 0 ) ?
"area of rhombus = 1 / 2 * d 1 * d 2 length of 1 st diagonal = 8 + 8 = 16 length of 2 nd diagonal = 3.5 + 3.5 = 7 area = 1 / 2 * 16 * 7 = 56 a is the answer"
rhombus_area(multiply(8, const_2), multiply(3.5, const_2))