 This problem asks us to find some missing measures of angles and a variable given information about some sides and measures of angles of the parallelogram. Whenever approaching these kind of problems the best thing to do is start by taking this given information and placing it on our illustration to get visual. We're told that side AB has a measurement of 2A, side DC has a measurement of 22, and the measure of angle C is 110 degrees. Let's start with the angles. If we know one angle in a parallelogram we can use that information to find the other three missing angles. We know that opposite angles, which would be angle A and angle C, are congruent, and we know that consecutive angles, which are any two angles that are next to each other, are supplementary, so they're going to add up to 180 degrees. It's a good idea to fill in the information on the illustration rather than to just fill in the answer because then you can have a visual that yes those two angles are opposite and are congruent, these two angles are opposite and congruent, and then you can work your way around and see that each of the four consecutive angles is indeed supplementary. That's a good check before you fill in your work. So we can go ahead and fill in the bottom, the measure of angle A is 110 degrees, the measure of angle B is 70 degrees, and the measure of angle D is also 70 degrees, and then the last piece of this is to find out what the value of A is, and that's where we see that A is given as one of the side measures, so we're going to go ahead knowing that opposite sides are congruent, we can set up the equation and solve for the missing variable. I know then that side AB is equal to side DC and doing, oops, not divided by A, divided by 2, we know then that A equals 11. Even though that was a fairly simple algebraic equation, you do want to make sure that you write down the equation because they will get tricky sometimes and it's good to have that visual.