How can 4 = 4 be equal to 4?

How can 4 = 4 be equal to 4?

(4-4) * 4 + 4 equals 4

Triangle function with acute angle
0 points
If there is an acute triangle, it needs to be constructed into a right triangle, and there is an angle A. find its sine, but the triangle it is in is not a right triangle. Is it right to construct a right triangle with an angle a, no matter what point it is higher than? Except for the height of a point
I have a problem here. To find the value of tangent 15, first draw a right triangle, angle a is 15 degrees, angle c is 90 degrees, I pass point B, and one side of the angle AB, form an angle of 15 degrees, and then intersect with AC at point D. at this time, the triangle abd is an isosceles triangle, and I can use BC divided by AC to find out the answer. If I change the way, I pass point d to make AB perpendicular to e, then is de divided by AE Is BC divided by AC?

Yes, you must not go over point a and make it high. You must let it be distributed in a right triangle. So you must not go over some points. You can go over any other two points

Calculation of acute triangle function
|Sin40-1 | + square 40 of radical 1-cos
Sin square 25 + radical (COS square 60-cos60 + 1) + sin square 65-3tan30
Calculation by computer: sin35
COS43°29′
tan68°23′

1) The square 40 of | sin40-1 | + radical 1-cos（