Cho ΔABC góc A = 90°, Cho ΔABC (góc A = 90°), Cho ΔABC; góc A = 90°, Cho ∆ABC (góc A = 90°), Cho  ΔABC ( góc A = 90°), Cho ∆ABC góc A=90°, Cho △ ABC ( góc A = 90° )