SOLUTION: Find the area in {{{ cm^2 }}}, of a right triangle that has one acute angle to twice the other, and has a hypotenuse equal to 5 cm. A) 6 B) {{{ 25sqrt(3)/8 }}} C) {{{ 25sqrt(3)/

Algebra ->  Triangles -> SOLUTION: Find the area in {{{ cm^2 }}}, of a right triangle that has one acute angle to twice the other, and has a hypotenuse equal to 5 cm. A) 6 B) {{{ 25sqrt(3)/8 }}} C) {{{ 25sqrt(3)/      Log On


   



Question 911743: Find the area in +cm%5E2+, of a right triangle that has one acute angle to twice the other, and has a hypotenuse equal to 5 cm.
A) 6
B) +25sqrt%283%29%2F8+
C) +25sqrt%283%29%2F4+
D) 12
E) +15sqrt%283%29%2F8+

Found 2 solutions by ichigo449, josmiceli:
Answer by ichigo449(30) About Me  (Show Source):
You can put this solution on YOUR website!
Let x be one of the acute angles. Then, as we have a right triangle, we obtain the equation: 3x+90=180, or x = 30 so 2x = 60, and we have a 30-60-90 triangle. Now, we have many ways to proceed to find an answer and I suggest you try to find 3 separate ways to get the area from this step. I will give you one as follows: Let H be the hypotenuse of the triangle, then for a 30-60-90 triangle the shortest side is H/2, and the middle length side is 1/2(H*sqrt(3)). Knowing these facts we can express the area as: H^2*sqrt(3)/8 by the regular area = 1/2(base*height) with base = H/2 and height = 1/2(H*sqrt(3)). We therefore conclude, by plugging in H = 5 that the answer is B. Have a nice day and good luck with your class.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let the smallest angle = +alpha+
The next larger angle = +2%2Aalpha+
It's a right triangle so the 3rd angle is +90+
+alpha+%2B+2%2Aalpha+%2B+90+=+180+
+3%2Aalpha+=+90+
+alpha+=+30+
+2%2Aalpha+=+60+
It is a 30-60-90 triangle
The sides are in the ratios:
+1+, +sqrt%283%29+, and +2+
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The actual lengths of the sides are:
+5%2F2+, +%285%2F2%29%2Asqrt%283%29+, and +5+
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+A+=+%281%2F2%29%2A%28+5%2F2+%29%2A%28+5%2F2%29%2Asqrt%283%29+
+A+=+%2825%2F8%29%2Asqrt%283%29+
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The answer is ( B )