Number of wires needed for a newly planted tree to be staked = 3
We are given that each wire is attached to the trunk 3 ft. above the ground and then anchored to the ground 4 ft. from the base of the tree.
Length of 1 wire used = 4+3 = 7feet.
Since three such wires are used for one tree,
Length of wire used for 1 tree = 3*7 =21 feet.
Now we have to find total wire needed for 6 such trees.
Length of wire required for 6 trees = 6 * Length of wire used for 1 tree
Length of wire required for 6 trees = 6 *21 = 216 feet.
Answer: Length of wire required to stake 6 trees is 216 feet.