The length of the hypotenuse of a right triangle is 157 units. The length of one leg of the triangle is 132. Lara wrote the following step to find the length of the unknown leg: Length of the unknown leg = 1572 − 1322 = 24,649 − 17,424 = 7,225 units

Which statement best explains whether Lara's step is correct or incorrect?

It is correct because the length of the unknown side is the difference of the lengths of the sides.
It is correct because the length of the unknown side is the difference of the squares of the sides.
It is incorrect because the length of the unknown side is the square root of 42,073.
It is incorrect because the length of the unknown side is the square root of 7,225.

The biologist has a second culture to examine. she knows that the population of the culture doubles every 15 minutes. after 1 hour and 15 minutes, her assistant found that 80,000 bacteria were present. a) what was the size of the initial population? b) predict the size of the culture at t=3 hours. what was the size of the population at 40 minutes? explain and justify your answers. c) create a graph of the population as a function of time. find an equation that can be used to predict the size of the population at any time t. d) examine the rate at which the bacteria culture is growing. how fast is the culture growing after 1 hour? after 1.5 hours? after 2 hours? use a time interval of h = 0.01 hours to estimate these rates. interpret these rates in terms of the context of the problem situation. how do these three rates compare?