You can
put this solution on YOUR website!sum of measures of interior angles=
180(n-2)
set it equal to 2100 and 2400
180(n-2)=2100
180n-360=2100
180n=2460
n=13.6667
180(n-2)=2400
180n-360=2400
180n=2760
n=15.3333
.5 or over round up
less than .5 round down
n=14 or 15
The polygon has 14 or 15 sides.