Which expression is equivalent to (+12)×5+7 ? A. 12+60

B. 12+12

C. 5+67

D. 5+12

Let the two sides of a right triangle be equal to one, which means that the hypotenuse is √2

Since cosa=adjacent side / hypotenuse

cos45=1/√2

We can rationalize the denominator by multiplying numerator and denominator by √2

√(2)/2

or if you prefer:  √(1/2)