If what I'm reading is correct, there are, in total, 135 yellow flowers. Since the sample space is only the color of flowers, we do not need any additional information except the total amount of flowers there are, as this is the amount that we are taking the yellow flowers from. The total amount of flowers is 315. To find our answer, divide the amount of yellow flowers by the total amount of flowers:
Two sides are given, either side of a vertical angle. So, the angles are the same. If the sides are proportional, the similarity will be by SAS (two sides, either side of an angle).
The ratios of short to long sides are ...
39/52 = (3·13)/(4·13) = 3/4
63/84 = (3·21)/(4·21) = 3/4
The sides are proportional and the angle between them is congruent, so ...
