Is it true that the order when dividing real number does not affect the answer

Sam claims that cos x =sin y if x and y are congruent angels. is sam correct ?

What is the perimeter of trapezoid jklm? + units 2 + + units 9 + units 9 + + units

Find the volume of the solid whose base is the region bounded by f(x), g(x) and the x-axis on the interval [0, 1], and whose cross-sections perpendicular to the y-axis are squares. your work must show the integral, but you may use your calculator to evaluate it. give 3 decimal places for your answe