What is the total cost of a 150.00 necklace if the sales tax is 6.5%

How do you solve a question like this?

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?

The graph shows the amount of money noah earned based on the number of lawns he cut. which list shows the dependent quantities in the graph?