Angle Relationships Use a calculator to find the approximate value of the expression. Round the answer to two decimal places.

The cosine of the complimentary angle of 60°

a. 0.50
b. 0.86
c. 0.25
d. 0.71

Please select the beast answer from the choices provided

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.