Answer:
First option: 3
Step-by-step explanation:
To solve for side 'a', use the Pythagorean Theorem
a² + b² = c²
where "c" is always the longest side called the hypotenuse,
"a" and "b" are the two shorter sides called legs.
Substitute c = 5 (hypotenuse) and b = 4
a² + b² = c²
a² + (4)² = (5)²
Square the numbers you know
a² + 16 = 25
Subtract 16 on both sides to isolate 'a'
a² = 25 - 16
a² = 9
Find the square root on both sides
a = √9
a = 3
