Pls answer ASAP I need by end of day #1

Answer:
m<A = 90° - m<B
(AB)^2 = (AC)^2 + (BC)^2
sin A = cos B
if <A = <B, then m<A = 45°
Answer:
Step-by-step explanation:
∠A+∠B=90 complementary angles ( the sum equal 90°)
∠A=90 degrees-∠B
tan A=sinA/cos A
AB²= AC² +BC² (Pythagorean theorem)
if angle A=angle B then the angles are 45 degrees
cos A=sin(90-A)
sin (a - b) = sin a.cos b - sin b.cos a
sin(90-A)=sin90.cosA-sinbAcos90 cos 90=0 and sin 90=1
sin(90-A)=1*cosA
sin(90-A)=cosA
the ones are in bold are right