Sunday

January 25, 2015

January 25, 2015

Posted by **mathfailure** on Tuesday, November 20, 2012 at 12:08pm.

- 15-75-90 triangle?? -
**Damon**, Tuesday, November 20, 2012 at 12:15pmsin 15 = sin 30/2 = sqrt ([1 -cos 30]/2)

cos 15 = cos 30/2 = sqrt( [1 + cos 30]/2)

but

we know cos 30 = (sqrt 3)/2

plug in

then

sin (90-t) = cos t

and cos (90-t) =sin t

to get sin and cos of 75

if you need tangents use tan = sin/cos

- 15-75-90 triangle?? -
**mathfailure**, Tuesday, November 20, 2012 at 12:19pmok ty alot

**Answer this Question**

**Related Questions**

math - The base in the Sierpinski triangle has 1 white triangle and zero black ...

Math : Geometry : Similar triangles - two right triangles are similar. the of ...

Math Help - The triangles are similar. Find the value of x. The triangles are ...

geometry - If you had two triangles, triangle RST and triangle UVW, and in ...

algebra - A set of 2 similar triangles was drawn in a design. One of the ...

Math - An equilateral triangle s divided into 4 congruent equilateral triangles...

Math - A pentagon is formed by putting together three identical equilateral ...

Algebra - represent the relationship between the number of triangles and the ...

geometry triangles - The sides of a triangle are 8,15 and 18 the shortest side ...

Pythagorean Theorem - 7. The following are the lengths of the sides of four ...