what is the formula for these triangles ?

sin 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

ok ty alot

To determine the formula for triangles, we need to specify which aspect of the triangle you are referring to. There are many different formulas related to triangles, such as the formulas for area, perimeter, angles, and side lengths.

1. Formula for the Area of a Triangle:
The most common formula to find the area of a triangle is:

Area = (base x height) / 2

To apply this formula, you need to know the length of the base and the perpendicular height of the triangle. Multiply the base length by the height, and then divide by 2 to get the area.

2. Formula for the Perimeter of a Triangle:
The perimeter of a triangle is the sum of the lengths of its three sides. If you know the lengths of all three sides, you can simply add them together to get the perimeter.

Perimeter = Side A + Side B + Side C

3. Formula for the Pythagorean Theorem:
If you have a right-angled triangle (90 degrees angle), you can use the Pythagorean theorem to find the length of one side if you know the lengths of the other two sides. The formula is:

a^2 + b^2 = c^2

Here, "a" and "b" represent the lengths of the two shorter sides (called the legs), and "c" represents the length of the hypotenuse (the side opposite the right angle).

4. Formulas for Trigonometric Ratios:
Trigonometry also plays a crucial role in triangles. There are three primary ratios: sine (sin), cosine (cos), and tangent (tan). These ratios relate the angles of a triangle to the lengths of its sides.

sin(A) = opposite / hypotenuse
cos(A) = adjacent / hypotenuse
tan(A) = opposite / adjacent

Here, "A" represents one of the angles in the triangle, and the lengths of the sides are given in relation to that angle.

Remember, specific triangle formulas may depend on the information you have about the triangle's sides, angles, or other measurements. So, make sure to identify what you know about the triangle first before applying a specific formula.