A 6-meter-high house must use a ladder above 6 meters. Otherwise, how can we get up there? In that case, 6.5 meters is definitely enough.

A six-meter-high place needs at least an eight-meter-long straight ladder, which is safe to climb. A six-meter straight ladder must have a certain slope. Generally speaking, this height should be at least one and a half meters above the ground. It is extremely unsafe to climb a ladder without a certain inclination, so a ladder six meters high and eight meters high is needed to meet the safety requirements. Generally speaking, a height of six meters requires a ladder of eight to nine meters, so it is much safer to climb a ladder of this length.