Answer: the diagonal is 10 units
Step-by-step explanation:
The rectangle has 2 parallel and equal sides. Each of the 4 angles in a rectangle is 90°. Therefore, the diagonal of the rectangle divides it into 2 equal right angle triangles and the diagonal represents the hypotenuse of both right triangles.
To determine the length of the diagonal of the rectangle, d, , we would apply Pythagoras theorem which is expressed as
Hypotenuse² = opposite side² + adjacent side²
Therefore
d² = 5² + (5√3)²
d² = 25 + 25×3 = 100
d = √100
d = 10 units