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:
![\[ \cos(\theta) = \frac{\text{Adjacent side}}{\text{Hypotenuse}} \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/2y9rxw95e15d3n2cq084mwg2105zra96x4.png)
3. Apply the cosine ratio: Substituting the given values:
![\[ \cos(60^\circ) = (2)/(a) \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/qzsnhsdj7sdpkmswh6xfg87aeseuxe7juv.png)
4. Calculate the value of
: We know from trigonometry that
.
5. Solve for a:
![\[ 0.5 = (2)/(a) \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/nwro6qx4st1xm12h6hx36fsz7bwl7ukqq5.png)
6. Calculate a:
![\[ a = (2)/(0.5) \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/4xhb1umxfbb0euiav3fc5y307t13jrjo5s.png)
![\[ a = 4 \]](https://img.qammunity.org/2022/formulas/mathematics/high-school/4h4pece1eyynmgmw67kn2v2mjvxn1qyocy.png)
Therefore, the answer is 4 units.