Notice that we can draw a right triangle inside the figure like this:
to find the perimeter, we must first find the hypotenuse of the triangle that we got. Then, using the pythagorean theorem, we have:
[tex]x=\sqrt[]{(5)^2+(12)^2}=\sqrt[]{25+144}=\sqrt[]{169}=13[/tex]
we have that the length of the missing side is 13 yd. then, the perimeter of the figure is:
[tex]P=10+12+15+13=50[/tex]
therefore, the perimeter is 50 yards
