(AMC8, 2000) The area of rectangle ABCD is 72. If point A and the midpoints of BC and CD are joined to form triangle, the area of that triangle is: A. 21 B. 27 C. 30 D. 36 E. 40

1. 2. ∠b and ∠y are right angles. 3.? 4.? which two statements are missing in steps 3 and 4? ∠x ≅ ∠c △abc ~ △zyx by the sas similarity theorem. ∠b ≅ ∠y △abc ~ △zyx by the sas similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem.