Trick and Concept: Most of the time (on the GMAT at least), when a Right Triangle is Involved, the GMAT will be testing 1 of 4 triangles: 30/60/90 ; 45/45/90 ; 3-4-5 ; 5-12-13
Another Concept: Given the 2 Legs of a Right Triangle and you need to find the Altitude from the 90 Degree Vertex to the Hypotenuse as the Base, find the Area first, then set the Area you find equal to = 1/2 * Hypotenuse * Altitude from 90 Degree Vertex
1st) The Triangle Crosses the Y-Axis at (0 , 12) ---- found by finding the Value of Y when X = 0 in the Equation
Similarly, the triangle crosses the X-Axis at (5 , 0) ---- found by finding the Value of X when Y = 0 in the Equation
2nd) We are told that the Line forms a Triangle with the 2 Axes. Using the Origin as a Vertex, the Line creates a Triangle with Legs of Length 5 Units and 12 Units. Therefore the Hypotenuse from Point (0 , 12) to Point (5 , 0) must = 13 Units
3rd) Area of Triangle = 1/2 * Leg * Leg = 1/2 * 12 * 5 = 30
Using the Hypotenuse = 13 as the BASE
Let the Altitude from the 90 Degree Vertex at the Origin = H
Area of Triangle = 30 = 1/2 * (13) * H
H = Altitude from the 90 Degree Vertex = 60/13
4th) the Other 2 Altitudes will be the 2 Legs of a Right Triangle ---- 5 and 12
SUM of all 3 Altitudes = 60/13 + 5 + 12 = 221/13 + 60/13 = 281/13
-Answer E-