As shown in the figure, in RT △ ABC, ∠ C = 90 °, am is the middle line on the side of BC, sin ∠ cam = 35, then the value of tanb is () A. 32B. 23C. 56D. 43

As shown in the figure, in RT △ ABC, ∠ C = 90 °, am is the middle line on the side of BC, sin ∠ cam = 35, then the value of tanb is () A. 32B. 23C. 56D. 43

In RT △ ACM, sin ∠ cam = CMAM = 35, let cm = 3x, then am = 5x. According to Pythagorean theorem, AC = AM2 − cm2 = 4x, and M is the midpoint of BC, ﹥ BC = 2cm = 6x, in RT △ ABC, tanb = ACBC = 4x6x = 23