why is sin(90 degrees) = 1. I know that that is the answer you get when you plug it into a calculator. I need an explanation as to why it equals 1

What is [tex] {7}^{98 + \sqrt{4} } - 3 \times (64 \div 2 + 4 - 36) \times a = a + 36[/tex]?

Since opening night, attendance at play a has increased steadily, while attendance at play b first rose and then fell. equations modeling the daily attendance y at each play are shown below, where x is the number of days since opening night. on what day(s) was the attendance the same at both plays? what was the attendance? play a: y = 8x + 191 play b: y = -x^2 + 26x + 126

How do the definitions, properties, and postulates you've learned about line segments, parallel lines, and angles to define the shapes of polygons