Answer
$JL \approx 3.9$
Work Step by Step
First, we want to know what angle is opposite the side in question. The angle that is opposite to the side we are looking for is $\angle K$, so let's plug in what we know into the formula for the law of cosines:
$(JL)^2 = 6.4^2 + 2.6^2 - 2(6.4)(2.6)$ cos $10.5^{\circ}$
Evaluate exponents first, according to order of operations:
$(JL)^2 = 40.96 + 6.76 - 2(6.4)(2.6)$ cos $10.5^{\circ}$
Add to simplify on the right side of the equation:
$(JL)^2 = 47.72 - 2(6.4)(2.6)$ cos $10.5^{\circ}$
Evaluate the right side of the equation:
$(JL)^2 \approx 14.9973$
Take the square root of both sides to solve:
$JL \approx 3.9$
