<p>If the measures of the acute angles of a right triangle are in the ratio of 4:5, what is the measure of the smallest angle in the triangle?</p>
<p>A) 10
B) 20
C) 40
D) 50
E) 80</p>
<p>This question was from the October 2013 SAT, and came in my Q&A service. If posting this is against CC rules, tell me and I'll take it down. I just couldn't find an explanation for the answer and I don't get it.</p>
<p>Thanks!</p>
<p>Okay, so we know that the sum of a triangles angles’ are 180 degrees. Now take out the right angle, which leaves us with 90 degrees left. We also know that we are dividing the angle into nine equal parts (4+5), and picking four of those to find the smallest angle. 90/9 = 10 degrees, and 10 * 4 = 40. The answer is C.</p>
<p>Thank you! That makes sense. Like, say marbles in ratio 5:7 (red and blue respectively) with 60 marbles. To find blue marbles: 5+7=12, 60/12 * 7 = 35 blue marbles (and then 25 red). So its just a proportion of (7/12)=(x/60). Easy, thanks again!</p>
<p>No problem, and good luck!</p>