How many 2-digit numbers can be formed from the digits 1 through 8 if each digit is only used once?

Both the red and blue line segments stretch from the center of the circle to a point on the circle. the length of the blue segment is 5. how long is the red line segment?

Can someone me and do the problem plz so i can understand it more better

If you double the input of a function and it results in half the output, and if you triple the input and it results in a third of the output, what can be guessed about the function? check all that apply.