What is the length of a diagonal of a square with a perimeter of 40 inches

14.1421356237 or sq root of 200

Step-by-step explanation:

A square has four equal sides therefore a perimeter of 40 means that each side is equal to 10 inches (40 inches of perimeter divided by 4 sides of square) Now the diagonal splits this square into 2 right triangles because squares have 4 right angles Pythagorean theorem is a squared + b squared = c squared. therefore a being 10 and b also being 10, 10 squared plus 10 squared = 200 and since a squared plus b squared = c squared that means that 200 is c squared but we want c so the square root of 200 is your answer. If this is for school I would ask your teacher's preference on simplification as there are two ways to write your answer but in my experience I would leave it squareroot(200) unless specified otherwise.