if you count the boxes that each side takes up you get the first side being equal to 5 units and the base being equal to 12 units. because this is a right triangle to find the length of the hypotenuse you have to use the Pythagorean equation. when you input the values into the equation you get 5^2 + 12^2 = 169 which square roots to 13. after doing this you have the length of the final side, now input them into the formula for the perimeter of a triangle which is a + b + c and you get a perimeter of 30 units,