
William W. answered 01/19/22
Experienced Tutor and Retired Engineer
I find the easiest way for me is to redraw the 3 triangles that are formed in this way side-by-side in the same orientation like this:
By doing that, it is easy for me to set up a similarity proportion.
In this case, we can see that using the medium size triangle and the small triangle we can say:
KM/LM = JM/KM or plugging in numbers:
12/x = 16/12 and cross multiplying:
12•12 = 16x
144 = 16x
x = 144/16
x = 9
So LM = 9
Once you know that LM = 9, you can add that to JM to get the length of the base JL. So JL = 9 + 16 = 25
Meaning the are of ΔLKJ = 1/2bh = 1/2(25)(12) = 150 square units