How do you determine an irrational number?

What is the range of the data below? .8090100

In δabc, if the length of side b is 3 centimeters and the measures of ∠b and ∠c are 45° and 60°, respectively, what is the length of side c to two decimal places?

The width of a rectangle is 20 units. can the perimeter p of the rectangle be 64 units when its length x is 11 units? no, because p = 2x + 2(20) no, because p ≠ 2x + 2(20) yes, because p ≠ 2x + 2(20) yes, because p = 2x + 2(20)