Answer:
<h2><em><u>x</u></em><em><u> </u></em><em><u>=</u></em><em><u> </u></em><em><u>39</u></em><em><u>°</u></em></h2>
Step-by-step explanation:
As per condition,
3x - 17° + 2x + 2° + 90° + 90° = 360°
<em>[</em><em>Since</em><em> </em><em>angle</em><em> </em><em>sum</em><em> </em><em>property</em><em> </em><em>of</em><em> </em><em>quadrilateral</em><em>]</em>
=> 3x + 2x - 17 + 2 + 90 + 90 = 360
=> 5x = 360 + 17 - 2 - 90 - 90
=> 5x = 195

=> <em><u>x = 39 (Ans)</u></em>
394+12.5+49.5+39+19.95=514.95,
25.7475+514.95=540.6975
12 lessons*20=240
Grand total is 780.6975
Basically, you could set these proportions up in two ways. You could set it up as 5/35=10/x, or you could set it up as 5/10=35/x. Either way, you will get the same answer. After setting one of them up, cross multiply. You should come out with 5x=350. Divide 350/5. Here you should get the answer of 70. 70 should be the length of LN