Pls answer a and b asap cus i need help thx

Yvaries directly as x. y =90 when x=6. find y when x=13

Urgent? will give brainliest to the first correct answer what is the area of the figure?

Identify all the cases where non-probability sampling is used when attempting to study the characteristics of a large city. studies on every subject in the population divide a population in groups and obtain a sample studies with a limited amount of time demonstrate existing traits in a population studies with the nth person selected