The difference between 12 and 2/3 of a number is 18

The number if marbles of different colors stored in a hat is listed below: 4 red marbles 10 green marbles 7 blue marbles. without looking in the hat, dan takes out a marble at random. he replaces the marble and then takes out another marble from the hat. what is the probability that dan takes out a blue marble in both draws?

Which of these tools or constructions is used to inscribe a hexagon inside a circle?

What is the circumference of a circle with an area of 50.24 cm²?