α=90-β ('stands for square, abc stands for side length, α β stands for two non-right angles, and ab side is opposite to these two angles respectively).

sinα=a/c，sinβ=b/c，sinα=cosβ=a/c，tgα=a/b=ctgβ

tgα=sinα/sinβ

sinα'+sinβ'= 1

Metaphysical theorem sin(α+β)=sinαcosβ+cosαsinβ.

Yuxuan theorem and universal formula,

Cosmic theorem cos(α+β)=cosαcosβ-sinβsinα.

The general formula TG (α+β) = tgα+tgβ/1-tgα tgβ.

About the circle, I mainly understand the relationship between radian and arc.

Circumference =2πr, area =πr', arc length = central angle * r.

The expression of the circle on the coordinate x'+y'=r'

These are probably the important formulas you want to ask. I didn't say them in junior high school, such as triangle area formula ... quadrilateral area ... you should know, right?

The center line of a triangle divides the triangle into two parts with equal area, the three centers of the triangle, the vertical center (the intersection of three perpendicular lines), the center of gravity (the intersection of the center line is called the center of mass, because it is divided into two parts with equal area, which is equivalent to its center of mass), and the inner heart (the intersection of the bisector of the angle is also the center of the inscribed circle of the triangle, so it is called the inner heart.