xác định tỉ lệ % trung bình tiền lương được gửi tiết kiệm trong quý 4/2017 là ( % , lấy 2 số thập phân )

Match each expression with its simplified form.

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angles. measure need asap

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?