Answer :
The length of the drape made from these panels will be 7.8 meters.
Explanation:
Since Ralph is sewing up three panels that are of different lengths each, the total length of the drape will be the sum of the lengths of all three panels.
The length of all three panels are 1.9 meters, 2.5 meters and 3.4 meters respectively. When we add all three lengths together, the sum total we get is 7.8 meters.
Total length of the drape: 1.9 + 2.5 + 3.4 = 7.8