1.25x8=10meters
100% (final-initial)/initial = % changed
100%(final-8 meters)/8 meters =25%
100%(final-8 meters)/8 meters/100 = (final-8 meters)/ 8 meters
25%/100=.25
So, (final-8 meters)/ 8=.25
(final-8meters)/8x8= final-8
.25x8= 2
So, final-8=2
final-8+8=final
2+8=10
Final=10 meters