Given the figure of the pond and the fact that the corners form a right triangle that is across from the string of flags, you can use the Pythagorean Theorem to solve for the width of the triangle that is formed by the flags:
a² + b² = c², where 'a' and 'b' represent the legs of the triangle and 'c' represents the diagonal or hypotenuse. Using 16 for 'a' and 20 for 'c':
16² + b² = 20²
256 + b² = 400
Subtract 256 from both sides: 256 - 256 + b² = 400 - 256 or b² = 144
Take the square root of both sides: √b² = √144 or b = 12 ft
