The Hall of Prayer for the New Year in Beijing Tiantan Park is a circular hall with a bottom diameter of 24.4 meters. How many square meters does it cover?

A: Area =πr2 (square) =π*( 12.2)2 (ordinary) = 148.84π (square meter).

Because it is not said to be accurate to a few decimal places, but as accurate as possible to 10 thousand decimal places. If π is 3. 14 159, the area is 467.5943 (square meters).

The circumference of the inner circle of the echo wall = 2π r = 2 * 3.14159 * 32.5 = 204.2 (m).