SOLUTION: The hypotenuse of a right triangle is 2 cm less than twice the shorter side. The longer side is 2 cm longer than the shorter side. How long is the hypotenuse?

Algebra ->  Pythagorean-theorem -> SOLUTION: The hypotenuse of a right triangle is 2 cm less than twice the shorter side. The longer side is 2 cm longer than the shorter side. How long is the hypotenuse?      Log On


   



Question 597607: The hypotenuse of a right triangle is 2 cm less than twice the shorter side. The longer side is 2 cm longer than the shorter side. How long is the hypotenuse?
Answer by math-vortex(648) About Me  (Show Source):
You can put this solution on YOUR website!
Hi, there--
.
Since this is a right triangle, we will use the Pythagorean Equation to find the lengths of the hypotenuse.
.
[I] Define the variables
Call a the length of the short leg.
Call b the length of the long leg.
Call c the hypotenuse.
.
[II] Create equation based on the given relationships
.
By the Pythagorean Theorem, we have
a%5E2%2Bb%5E2=c%5E2
.
In algebra, "the hypotenuse is 2 cm less than twice the shorter side" can be written as
c=2%2Aa-2
.
Likewise, we can write "the longer side is 2 cm longer that the shorter side" as
b=a%2B2
.
.
[III] Solve the system of equations
Substitute a+2 for b and 2*a-2 for c in the Pythagorean Equation.
a%5E2%2B%28a%2B2%29%5E2=%282%2Aa-2%29%5E2
.
Use the distributive property to clear the parentheses.
a%5E2%2B%28a%5E2%2B4a%2B4%29=4%2Aa%5E2-8a%2B4
.
Simplify and solve for a.
2a%5E2%2B4a%2B4=4%2Aa%5E2-8a%2B4
-2a%5E2%2B12a=0
.
Factor the quadratic polynomial on the left side of the equation.
-2%2A%28a-6%29=0
.
By the Zero Product Property, is -2 times (a-6) equals zero, then (a-6) must equal zero.
a-6=0
a=6
.
The equation a=6 means that the shorter leg of the triangle is 6 cm.
The longer leg is a+2 = 6+2 = 8 cm.
The hypotenuse is 2*a-2 = 2(6)-2 = 10 cm.
.
.
[IV] Check your work
Do these values satisfy a right triangle?
a%5E2%2Bb%5E2=c%5E2
%286%29%5E2%2B%288%29%5E2=%2810%29%5E2
36%2B64=100
100=100
Correct!
.
THe hypotenuse is 10 cm.
.
I hope this helps!
.
Ms.Figgy
math.in.the.vortex@gmail.com