Answer:
d = 437 yd
Explanation:
Use Pythagoras Theorem where sides a, b, c make up a right angle triangle
Here we can see there is a right angle triangle with sides 450 yd, 600 yd, (d + 313) yd. Here (d + 313) is the longest side also called the hypotenuse.
Using the formula:
opposite² + adjacent² = hypotenuse²
a² + b² = c²
450² + 600² = (d + 313)²
202500 + 360000 = (d + 313)²
562500 = (d + 313)²
d + 313 = √562500
d + 313 = 750
d = 750 - 313 = 437 yd