SOLUTION: The legs of a right triangle are in the ratio 1:2. The angle bisector to the short leg divides it into two segments, one of which is 1cm longer than the other. Express the perim

Algebra ->  Triangles -> SOLUTION: The legs of a right triangle are in the ratio 1:2. The angle bisector to the short leg divides it into two segments, one of which is 1cm longer than the other. Express the perim      Log On


   



Question 1177803: The legs of a right triangle are in the ratio 1:2. The
angle bisector to the short leg divides it into two
segments, one of which is 1cm longer than the other.
Express the perimeter of the triangle in simplest
radical form.

Answer by Edwin McCravy(20059) About Me  (Show Source):
You can put this solution on YOUR website!
The legs of a right triangle are in the ratio 1:2.
That means the right triangle is similar to this right triangle



The angle bisector to the short leg divides it into two
segments, one of which is 1cm longer than the other.

We draw the angle bisector (in green), and let the two segments be 
x and x+1:



A famous theorem says:

The bisector of an angle of a triangle divides the opposite side into
segments that are proportional to the adjacent sides.

We also know the ratio is 2:√5 from the similar right triangle at the top.

x%2F%28x%2B1%29=2%2Fsqrt%285%29

Solve for x and get

x=4%2B2sqrt%285%29

So the right side of the triangle is %284%2B2sqrt%285%29%29%2B%285%2B2sqrt%285%29%29 = 9%2B4sqrt%285%29

Since the side corresponding to 1 is 9+4√5, we know the scale factor is
9+4√5.

Since this triangle (the one at the top)



has perimeter 3+√5, we just multiply that by the scale factor:

%283%2Bsqrt%285%29%29%289%2B4sqrt%285%29%29

and get 

47+%2B+21sqrt%285%29   <--answer

Edwin