The measure of an angle is 19°. What is the measure of its complementary angle?

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

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.

What is the solution to this system of equations? y= 2x - 3.5 x - 2y = -14