a person enters a building on the first floor and runs up to the third floor in 30 seconds at this rate, how many seconds will it take the person to run from the first floor up to the 6th floor in the building?

The area (a) of a circle with a radius of r is given by the formula and its diameter (d) is given by d=2r. arrange the equations in the correct sequence to rewrite the formula for diameter in terms of the area of the circle.