D __7. DABCD at the right is a parallelogram with |BC| = 3x + 5cm, |DC| = 4x - 5 cm, and JADI = 6x - 10 cm. Determine the length of BC. A 6X-10 A. 5 cm C. 15 cm B. 11 cm D. 20 cm 8. From the same figure in #7, what is the perimeter of the parallelogram? A. 50cm C. 70 cm B. 60 cm D. 80 cm C. 9. Given isosceles trapezoid ACDF at the right, with CDI = 6x - 6 cm and |AF| = 9x - 3 cm, find the length of median BE if x = 5 cm. A. 24 cm C. 42 cm B B. 33 cm D. 75 cm D - E F А G 10. From the same figure in #9, what is the length of FG? A. 7 cm C. 12 cm B. 9 cm D. 24 cm​