Answer: Cos0 = 3/5
Step-by-step explanation: In order to calculate the value of Cos0, we would have to apply the trigonometrical ratio of
Cos0 = adjacent/hypotenuse
The adjacent is already given as 3 units (the side that lies between the reference angle and the right angle).
In order to calculate the hypotenuse (unknown side, which we shall label as X), we shall apply the Pythagoras theorem, which is;
X² = 3² + 4²
X² = 9 + 16
X² = 25
Adding the square root sign to both sides of the equation, we now have
X = √25
X = 5
Now that we have the adjacent (3 units) and the hypotenuse (5 units), the cosine of the unknown angle can be calculated thus,
Cos0 = adjacent/hypotenuse
Cos0 = 3/5
