In triangle ABC, angle C is 90 degrees AB = 5, sin A = 3/5 find AC

Given:
right-angled triangle ABC;
angle C = 90;
sin A = 3/5;
AB = 5;
Find: AC -?
Solution:
1) Consider a right-angled triangle ABC. The sine of the angle in a right-angled triangle is equal to the ratio of the opposite leg to the hypotenuse. Hence:
sin A = BC / AB;
BC = sin A * AB;
BC = 3/5 * 5;
BC = (3 * 5) / 5;
BC = (3 * 1) / 1;
BC = 3;
2) by the Pythagorean theorem (the square of the hypotenuse is equal to the sum of the squares of the legs):
AC ^ 2 + BC ^ 2 = AB ^ 2;
AC ^ 2 = AB ^ 2 – BC ^ 2;
AC ^ 2 = 5 ^ 2 – 3 ^ 2;
AC ^ 2 = 25 – 9;
AC ^ 2 = 16;
AC = 4.
Answer: AC = 4.