Question 429483
Suppose the length of the altitude is h.


We know that the area of the 3-4-5 triangle is (3*4)/2 = 6 (this works because the triangle is a right triangle). Since h is the height from the hypotenuse, we can express the area in terms of another base (the hypotenuse) and its corresponding height:


{{{6 = (5h)/2}}}


{{{12 = 5h}}} --> {{{h = 12/5}}}.