MATH
posted by THAMI .
A LADDER IS LEANING AGAINST THE WALL. IF THE LADDER REACHES A HEIGHT OF 12M UP THE WALL AND HAS ITS FOOT 5M AWAY FROM IT ,CULCULATE THE LENGTH OF THE LADDER?

So for this you would use the Pythagorean Theorm.
The formula is a^2 + b^2 = c^2, where c is the hypotenuse of the triangle.
So if you know that the ladder reaches the height of 12m, that would be the hypotenuse in the triangle. 5m would be one of the legs in the triangle.
Therefore, calculate 5m^2 + ?^2 = 12m^2. 
actually, 12 is one of the legs. The ladder is the hypotenuse. Make a diagram to see why.
Think 51213 Pythagorean triple