Cho tam giác ABCD. Chứng minh rằng nếu vectơ AB = vectơ DC thì vectơ AD = vectơ BC

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 the following is the shape of a cross section of the figure shown below

15m is what percent of 60m; 3m; 30m; 1.5 km? the last one is km not m