Well just think, what is the ten thousands place? 1 right by 6. From this to round you look at the previous number 6, anything 5 or above will be rounded up making the 1 into a 2, anything lower than a 5 will become rounded down making the 1 stay the same, but instead making it into 10,000
So the answer would be 20,000
The doorstop is a triangular prism. volume of the triangular prism is the area of the base times the height
area of the base: 1/2 * 10*6=30cm²
height: 2.5cm
Volume: 30cm²*2.5cm=75cm³
weight: 75cm³*8.6g/cm³=645 grams
She can become an excellent writer if she continues to work at it.