Can someine explain this i'm confused on what it's asking

Find the circumference of a pizza with a diameter of 10 inches round to the nearest tenth

In a coastal town, the humidity, measured in grams of water per kilogram of air, increases by 43% for every 1 degree celsius increase in temperature. a scientist observes that the humidity on monday morning is 5.75 grams per kilogram. he wants to know how much the temperature must increase for the humidity to reach at least 49.17 grams per kilogram. let t represent the increase in temperature, in degrees celsius, from monday morning's observation. write an inequality to represent the situation, and use it to determine the desired temperature increase.

There is a linear relationship between a salesperson sales and her weekly income.if her sales are $200 her income is $500 and if her sales are 1,200 her income is $600.what is the relationship between sales and income