Explanation:
Sin 30 = opposite side / hypotenuse
Sin 30 = 5/ c
0.5 = 5/c
0.5c = 5
C = 10
Since it is a rt angled triangle, you can use Pythagoras theorem to solve for b
C² = a² + b²
10² =5² + b²
b² = 100- 25
b² =75
b = square root of 75
b = 5root 3 (write with the root sign)