a toxic radioactive substance with a density of 4 milligrams per square centimeter is detected in the ventilating ducts of a nuclear processing building that was used 35 years ago. if the half- life of the substance is 20 years, what was the density of the substance when it was deposited 55 years ago?

1234567891011 match the reasons with the statements in the proof. given: j | | k m 1 = m 3 prove: l | | m 1. j||k, m∠3 = m∠1 if lines are ||, then corresponding angles are =. 2. m∠1 = m∠2 if alternate interior angles are =, then lines are ||. 3. m∠2 = m∠3 substitution 4. l||m given

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?

The function f(x) = 14,600(1.1)* represents the population of a town x years after it was established. what was the original population of the town?