What is the cofunction of cos 2pi/ 9

The cofunction of cos is sin(90-x)

90 degrees is equal to PI/2

The cofunction becomes sin(PI/2 - 2PI/9)

Rewrite both fractions to have a common denominator:

PI/2 = 9PI/18

2PI/9 = 4PI/18

Now you have sin(9PI/18 - 4PI/18)

Simplify:

Sin(5PI/18)

b. an equilateral triangle inscribed in a circle

step-by-step explanation:

we are given the figure of two circles having a triangle inside.

now, we know that,

"when a figure is lying inside an another figure, then the outside figure is known as circumscribed figure and the figure lying inside is referred to as the inscribed figure".

as we see that, the circles are containing the triangle completely.

thus, the circles are the circumscribed figures and the triangle is the inscribed figure.

hence, we get, 'an equilateral triangle is inscribed in a circle'.

im alright what do you need

step-by-step explanation: