You enter a lottery where you select 5 number from 1 - 30 without duplicating numbers. How many possible combinations of numbers are there?

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters

The sum of 5consecutive even numbers is 100. what is the first number in this sequence?

Iwill arward ! , i if bt ≅ eu , bu ≅ et , prove: ∠b ≅ ∠e. fill in the blanks: draw segment ut ≅ bt≅ bu ≅ △ubt ≅ △