So 2.5 km is 1/2 the distance around the lake lake=circle therefor 2.5=1/2circumference we must find the circumference to find radius then diameter to find the distnace from one side to the other 2.5=1/2 circumference multipiliy by 2 5=circumferneece
circumference=2pir or pid r=radius=distance from middle of circle to outer edge d=diameter=2 times rasius, or lonest line drawn in circle (we want to find this to see how far it is from one end of the circle to ther other)
5=circumference=pid 5=pid divide both sides by pi 5/pi=d aprox pi to 3.14 for the problem 5/3.14=d=1.59 rounded so A. 1.59 km
B. 1.5 km per hour swim and 3km per hour walking we see that 1.59 is greater than 1.5 so it wil take more than 1 hour to swim we see that 2.5 is smaller than 3 so it will take less than 1 hour to walk it is faster to walk