Which expression represents the number of possible combinations of n items taken r at a time?

Jeremy drew a polygon with four right angles and four sides with the same length. what kinds of polygon did Jeremy draw?

What is the area of this polygon?

B. After school, Alex skateboards at the same constant speed to his friend's house. It takes him 10 minutes, Write the fraction that represents constant speed, C, if he travels a distance of y.

vicki has 50 inch roll of ribbon. she used 3 feet of the ribbon to wrap a gift. how many inches of ribbon does she have left?

What is the next number in 20, 10, 5, 15?

Amelia stars reading at 3: 25 and reads for 15 minute. What type of angle is formed by the hour and minute hands of the clock wen Amelia fineshes reading

Six added 3 times to a number is equal to 4 less then 5 times the number what is the number A. 5 B. - 10 C. 10 D. - 5

Find the volume of a cylinder which has a radius of 14 cm and a height of 9 cm.

What is the product? (9t-4) (-9t-4) a) - 81t^2-16 b) - 81t^2+16 c) - 81t^2 - 72t+16 d) - 81t^2 + 72t+16

The mean weight of 8 girls is 55kg and the mean weight of a group of boys if 52kg. the mean weight of all the students is 53.2kg. how many boys are there?