 Hello and welcome to the session. Today I'll help you solve this question. The question says, find the angle measure X in the following figure. The key idea to be used in this question says, the sum of the angles of a quadrilateral is 360 degree. Now let's see the solution. Now in the figure I have marked this angle as 1 and this angle as 2. As you can see the angle 1 here is shown as 90 degrees and angle 1 and angle 2 they form a linear pair. So we can say, angle 1 plus angle 2 is equal to 180 degrees because they form a linear pair. Now angle 1 is given to be 90 degrees. So we have 90 degrees plus angle 2 is equal to 180 degrees. Now transposing this 90 to the right hand side we have angle 2 is equal to 180 degrees minus 90 degrees. Now this implies, angle 2 is equal to 90 degrees. Now consider this figure. In this quadrilateral the measures of the angles are angle 2 that is 90 degrees, 60 degrees, 70 degrees and X. So by using the key idea which says that the sum of the angles of a quadrilateral is 360 degrees we can have angle 2 plus 60 degrees plus 70 degrees plus X is equal to 360 degrees. Now we have found angle 2 as 90 degrees therefore substituting the value for angle 2 we have 90 degrees plus 60 degrees plus 70 degrees plus X is equal to 360 degrees. Now this implies 90 degrees plus 60 degrees plus 70 degrees is 220 degrees therefore X plus 220 degrees is equal to 360 degrees. Now we transpose this 220 to the right hand side so we have X is equal to 360 degrees minus 220 degrees which implies X equal to 140 degrees. Therefore a final answer in this case would be 140 degrees. Hope you enjoyed the session. Have a good day.