Question 1100997
<br>Add points D(0,12) and E(6,12) to the diagram, and call the origin point O.<br>
The area of triangle ABC is the area of rectangle OBED, minus the areas of the three right triangles AOB, BEC, and CDA.<br>
The area of rectangle OBED is 6*12 = 72.
The area of triangle AOB is 6*8/2 = 24.
The area of triangle BEC is 12(6-x)/2 = 36-6x.
The area of triangle CDA is 4*x/2 = 2x.<br>
The area of triangle ABC is {{{72 - 24 - (36-6x) - 2x = 12+4x}}}
Since the area is supposed to be 20,
{{{12+4x = 20}}}
{{{4x = 8}}}
{{{x = 2}}}<br>
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