The correct option is c.
The exact length of side a is 4 units.
To find the length of side a in the given right-angled triangle, we can use trigonometric ratios. Here are the steps:
1. Identify the known sides and angles: In the triangle, we know the length of side BC (which is 2 units) and angle ACB (which is 60 degrees). We need to find the length of side
.
2. Choose the appropriate trigonometric ratio: Since we have the adjacent side BC and we need to find the hypotenuse
, we can use the cosine ratio, which is given by:
3. Apply the cosine ratio: Substituting the given values:
4. Calculate the value of
: We know from trigonometry that
.
5. Solve for a:
6. Calculate a:
Therefore, the answer is 4 units.