Hello!
We are given a 45° angle. We have the length of the hypotenuse, along with a being the opposite side. If we think of this in terms of trigonometric ratios, we know that the sine deals with the opposite side and hypotenuse. Let's find our sine.
sin45≈0.71
As the sine is the opposite side divided by the hypotenuse, we get the equation below.
a/6=0.71
To find a, we multiply both sides of this equation b 6.
a=4.26
Therefore, a is about 4.26
I hope this helps!