The ladder leaning against the wall forms a right angled triangle with the gound and the wall. So we can use the formula:a² + b² = c²The ladder is the hypotenuse c²The vertical leg is b²The base or horizontal leg is a²We need to find the length of the base a², so:a² = c² - b²a² = 5² - 4²a² = 25 - 16a² = 9a = √9a = 3<span>Therefore the bottom of the ladder must be 3 feet from the wall.
Example: </span>If the 24 foot ladder is leaned on the house with the bottom 8 feet from the base the wall of the house, then it will form a right angled triangle.The base of the triangle will be 8 feet while the 24 foot ladder forms the hypotenuse. We need to find out the height from the base of that wall to the point the ladder touches the wall.Let the hypotenuse be CLet the base be BLet the height be AWe use this formula: A squared + B squared = C squaredA sq + 8 sq = 24 sqA sq + 64 = 576A sq = 576 - 64A sq = 512A = Square root 512A = 22.6To the nearest 10th this will be 23<span>So the answer is 23 feet.</span>
