3rd option.
at least shows that the number can be equal to 2, and also that 2 should be the smallest possible value of the number.
Area of a circle: πr²
Data:
diameter: 21 cm
radius=diameter/2=21 cm/2=10.5 cm
area of this circle: π(10.5 cm)²=110.25π cm² (≈346.36 cm²)
Answer: area=110.25π cm²
For 1. To estimate how many sports cards Alberto had, you would round each number to the nearest ten, so 318 would become 320. 273 would then become 270. You would then add those two and would get 590. So, Alberto had 590 sports cards (estimated). If you were looking for the actual answer (not estimated) , you would get 591.
