A) because it is 2/3 past 1
All 45 45 90 triangles sides are equal to x, x, and xsqrt2. which is the biggest side. So here x(11) and x(11) are both given. the answer to the x shown on the triangle is xsqrt2
Answer: 1
13pi/2 can be simplified onto 6 pi/2, so it goes around the unit circle 6 times and left with pi/2. the coordinates of pi/2 is (0,1). the trigonometric function sin is y/r. since r is always 1 on the unit circle, the answer is the y value, in this case it is 1.