Mean of 245,250,251,253,258,264,267,269,273 ,276

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

Ratio of circumference to diameter example plz i need to now what it looks like.

Adan has decided to purchase an $9000 car. he plans on putting 20% down toward the purchase and financing the rest at 7.9% interest rate for 3 years. find his monthly payment a) $225.29 b) $298.81 c) $204.78 d) $236.89