Can someone please help me with math

Acircle has a circumference of 7.850 units. what is its radius?

Use the given information to determine the exact trigonometric value.

Astandard deck of cards contains 52 cards. one card is selected from the deck. (a) compute the probability of randomly selecting a diamond or heart. (type an integer or a decimal rounded to three decimal places as needed.) (b) compute the probability of randomly selecting a diamond or heart or club. (type an integer or a decimal rounded to three decimal places as needed.) (c) compute the probability of randomly selecting queen or club. (type an integer or a decimal rounded to three decimal places as needed.)