How much would it cost to buy 1/2 of a pound of star washers, 3/4 of a pound of lock washers, and 1/2 of a pound of square washers?

Quick translate "x is 12 units from 20" into an equation. what are the values of x being described? if you can answer any of my other questions that'd be great too

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?

Qrst is a parallelogram. determine the measure of ∠q pls