CD / / EF / / AB, CD = 2, ab = 4. EF bisects the area of trapezoid ABCD and finds the length of EF CD / / EF / / AB, CD = 2, ab = 4. EF bisects the area of the trapezoid ABCD to find the length of EF (requires a problem-solving process)

CD / / EF / / AB, CD = 2, ab = 4. EF bisects the area of trapezoid ABCD and finds the length of EF CD / / EF / / AB, CD = 2, ab = 4. EF bisects the area of the trapezoid ABCD to find the length of EF (requires a problem-solving process)

(CD + EF) H1 = 1 / 2 * (CD + AB) H (H1: EF, the height of the trapezoid formed by CD, H: the height of the original trapezoid) = > (2 + EF) H1 = 3H = > H1 / h = 3 / (2 + EF) make DG parallel to BC intersection through D, EF, AB parallel to g, H = > dcbh is parallelogram, BH = CD = 2 = > ah = 4-2 = 2EG = ef-cd = ef-2h1, h is the height of triangle DEG, Dah respectively