Ladder sliding down a wall.....grab the Pythagorean Theorem!

The top of a 25-foot ladder is sliding down a vertical wall at a constant rate of 3 feet per minute. When the top of the ladder is 7 feet from the ground, how far is the bottom of the ladder from the wall? 

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A right triangle is formed with a height of 7 ft (up the wall) and a hypotenuse of 25 ft (the ladder). 

a² + b² = c²   {the pythagorean theorem}

7² + b² = 25²   {a and b are the legs and c is the hypotenuse}
49 + b² = 625   {evaluated the exponents}
b² = 576   {subtracted 49 from each side}
b = 24   {took the square root of each side} 

the bottom of the ladder is 24 ft from the wall

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