2007-09-20 17:14:00 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
you know what a 30-60-90 triangle is, right? Just in case: the side opposite of the angle that is 30 degrees is 1, the one opposite 60 degrees is root 3, and the hypotenuse is 2. That's just the ratio though.
cosine is adjacent/hypotenuse, so the side adjacent to the 30 degree angle is root 3 and the hypotenuse is 2, so root three over two.
2007-09-20 17:27:29 · answer #1 · answered by Zack Wilder 3 · 0⤊ 0⤋
The 30/60/90 right triangle with smallest size of 1 has a hypotenuse of 2 and a third side of sqrt(3) . The cos of 30 degrees for this triangle would be 1/2 sqrt(3). q.e.d.
2007-09-20 17:24:52 · answer #2 · answered by cattbarf 7 · 0⤊ 0⤋
With a 30-60-90 right triangle.
The triangle in question has sides in the ratio of 1, sqrt(3), 2. The 30° angle is adjacent to the side of length sqrt(3) and opposite the side of length 1, with the side of length 2 as the hypotenuse. The cosine is defined as the ratio of the adjacent side to the hypotenuse, thus the ratio of sqrt(3) to 2.
2007-09-20 17:27:06 · answer #3 · answered by Anonymous · 0⤊ 0⤋
That is not the right answer!
Draw a circle in wich r=1... draw line at 30 degress and draw x and Y axis.
This will be equivalent to form a triangle with three equal sides... measure of the side =1
We can deduct then that there will be then a triangle rectangle with hipotenuse=1 and one cateto=0.5... from pitagoras...
1^2=0.5^2+L^2
other cateto = square root of (1-0.5^2)
Then the cos of the angle will be: L/Hipothenuse
Cos 30 = square root of (1-0.5^2) = 0.866
2007-09-20 17:31:16 · answer #4 · answered by vceronc 1 · 0⤊ 0⤋