Answer:
14.45 feet
Step-by-step explanation:
The set up is a right angled triangle;
The length of the ladder = hypotenuse = 15foot
The base of the ladder is the adjacent = 4feet
The height of th house is the opposite = x
Using the pythagoras theorem;
hyp² = opp² + adj²
15² = opp²+4²
opp² = 15²- 4²
opp² = 225 - 16
opp² = 209
opp = 14.45feet
Hence the ladder reaches 14.45 feet up the house
