... = 1 x y Bµi 2: Cho tam gi¸c ABC vu«ng t¹i A, ®êng cao AH, biÕt AH = 15 ; BH = 9. TÝnh HC; AB; AC; µ µ B; C. Bµi gi¶i µ 0 AH 15 tgB 1, 666 B 59 1& apos; HB 9 = = ≈ ⇒ ≈ µ 0 0 0 Do®ã C 90 59 1& apos; ... 59& apos;≈ − ≈ 2 2 AH 225 AH HB.HC HC 25cm HB 9 = ⇔ = = = H B C A 1 5 c m 9 c m 2 2 2 2 AB 15 9 306 17 ,5cm AC 15 25 850 29, 2cm = + = ≈ = + = ≈ Bài 3: Cho ∆ABC có AB = 6 cm, AC = 6 cm, BC = 12 ... 2 2 2 2 2 2 AB AC 6 3 6 14 4 AB AC BC BC 12 14 4 Theo§L Pitago ®¶o th× ABC vu«ng t¹i A + = + = ⇒ + = = = ∆ $ $ µ µ 0 0 0 0 0 AC 6 sinB 0,5 B 30 BC 12 B C 90 C 90 30 60 AH.BC AB.AC (HÖ...