Please explain I don’t get it

1) 15.5<a<16.5

2) 9.5<b<10.5

3)550<<650

4)5500<<6500

5)5950<<6050

6)5995<<6005

7)5999.5<<6000.5

Step-by-step explanation:

To do these you're essentially looking for the range that the answser could be if it were an estimation. for example:

for 1, the answer is 16, but if it were 15.5 or anything higher you would round up to 16, or if it were anything below 16.5 you would round down to 16.

Note that that is not if it were 16.5 because that would mean you would round up to 17.  A must be less than (<) 16.5, while in the other sense, 15.5 it can be that exact number so you have a

For ones like 3 its the same thing. But if you were always rounding to the hundreds place, it could be anything above or equal to 550, since you are rounding up to the closest hundred. And it can also be less that 650.

step-by-step explanation:

∆abc has the points a(1, 7), b(-2, 2), and c(4, 2) as its vertices. formed with the point d(1, 2) as its third vertex, then ∆abd is triangle.