What is the approximate side length of the square if the diagonal is 3?

Step-by-step explanation:

The diagonal of a square is the same thing as the hypotenuse of a right triangle.  This right triangle is a 45-45-90 since the sides are made up of sides of a square which all measure the same length, x.

Using Pythagorean's Theorem,

 and

 and

 and taking the square root of both sides gives us that

 which simplifies to

 I'm assuming that your teacher has told you about rationalizing the denominator when you've got a radical there, so we will do that by multiplying by   :

 which gives us

step-by-step explanation:

given perimeter: 28cm

length: 9cm

atp,

2(l+w)=p of the reactangle

2(9+x)=28

18+2x=28

2x=28-18

x=10/2

x=5

therefore width is 5 cm