## Elementary Algebra

Let's assume the shortest side is x. Then, the three sides of the triangle are $x$, $2x$, and $x+10$. The sum of the sides is the perimeter, so $x+2x+(x+10)=70$. Combining terms gives: $4x+10 = 70$ Subtract both sides by 10: $4x = 60$ Divide both sides by 4: $x = \frac {60}{4} = 15$ Plugging in the value for $x$ into $x+10$ and $2x$ gives that the length of the 3 sides are 15, 25, and 30.