If the half life of a substance is 4 weeks, how long will it take for 400 mg of this substance to decay to 25 mg?

Asquare has a side that measures 11 units. what is the area of a circle with a circumference that equals the perimeter of the square? use 3.14 for π, and round your answer to the nearest hundredth. 1519.76 units2 379.94 units2 616.56 units2 154.14 units2

Which polygon is she in the process of constructing ?

Isaac wants the equation below to have no solution when the missing number is placed in the box. which number should he place in the box?