Wednesday, August 21, 2013

the hypotenuse of a right triangle is 24 ft long. the length of one leg is 6 feet more than the other. find the length of the legs.

c=24 
Clearly the side we know the least about is the shortest so... 
a=x 
the length of one leg is 6 feet more than the other means... 
b=x+6 
So our equation is: 
x%5E2%2B%28x%2B6%29%5E2=24%5E2 
so here we go... 
x%5E2%2B%28x%5E2%2B12x%2B36%29=576 

2x%5E2%2B12x-540=0 
divide by 2... 
x%5E2%2B6x-270 

but this quadratic cannot be factored - so we use the quadratic formula 
x+=+%28-6+%2B-+sqrt%28+6%5E2-4%2A1%2A%28-270%29+%29%29%2F2+ 


From which the negative solution can be discarded (why?) 
therefore... 
x=3sqrt%2831%29-3 
and so... 
{{a=3sqrt(31)-3}}} 
{{b=3sqrt(31)+3}}} 
c=24

No comments: