Answer:
D.
Explanation:
Bottom of the ladder is base, a = 3 ft
Top of the ladder from the ground is the perpendicular, b = 4 ft
We have to find the length of ladder, c = ?
So we'll use Pythagoras theorem
c² = a²+b²
c² = 3²+4²
c² = 9+16
c² = 25
Taking square root on both sides, we'll get
c = 5 feet