We are asked to solve for the value of a2 and we can solve this problem by applying the Law of Cosines such as the formula is shown below:
a² = b² + c² - 2bccosA
We are given with the following values:
b=3
c=3
A=45°
Let us solve by substituting these values into the formula such as shown below:
a² = 3² + 3² - 2*3*3*cos 45° , squared the values and perform addition and subtraction
a ² = 9 + 9 - 18cos45°
a² = 5.27
The answer for the length of a² is 5.27 which is letter "A".