In triangle ABC, angle-C = 90 degrees, angle-AB = 30, AC = 6 root of 21. Find Sim-A?

Consider a triangle ABC, angle C = 90, AB – hypotenuse AB = 30 cm, AC and CB – legs, and AC = 6 * √21 cm.
By the Pythagorean theorem, we define the missing leg of the СВ:
CB = √ (AB²-AC²) = √ (30²- (6 * √21) ² = √ (144) = 12 cm.
The sine of the angle is equal to the ratio of the opposite leg to the hypotenuse:
sin A = CB / AB = 12/30 = 0.4
Answer: sin A = 0.4