Need help with math triangle question in image. Thank you

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

Use set buikder notation to represent the following set: {, -2, -1, 0}

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?