In any right triangle with acute angles x and y, then
The sum of x and y is 90 degrees
Then for part (1)
Since triangle XYZ is a right angle at Z
Then
Then X and Y are complementary angles
Part (2)
sin X = opposite/hypotenuse
sin Y = opposite/hypotenuse
cos X = adjacent/hypotenuse
cos Y = adjacent/hypotenuse
Part (3)
Part (4)
Since sin = cos, then
The sum of the 2 angles must be 90
One of them is 23 degrees, then the other must be
The answer is