In a right triangle the cosine of an acute angle 1/2 and the hypotenuse measures 7 inches. What is the length of the side of the triangle adjacent to this angle?

Option A for first question.

Options C and D for second question.

Step-by-step explanation:

Which set of numbers does 13−−√ belong?

The answer is option A: irrational numbers

This is because the square root of 13 is a decimal number that does not end. Irrational numbers are those which cannot be expressed in a ratio form  and also cannot be written as a simple fraction.

To which sets of numbers does −1/4 belong?

The answer is option C and D: rational numbers  and real numbers

This is because real numbers are made up of rational and irrational numbers. We also know that every real number is either a rational number or irrational number.