A newly planted tree needs to be stacked with wires. each wire is attached to the trunk 3 feet above the ground, and then anchored to the ground 4 feet from the base of the tree. how much wire needed for 6 trees.

Solution:

The wire , the distance away from the  trunk and the trunk forms a right  angled triangle

wire = hypotenuse

trunk = height

The distance on the ground  to the peg from the trunk  = base

Each wire is attached to the trunk 3 feet above the ground, and then anchored to the ground 4 feet from the base of the tree

Therefore,

height = 3 feet

other leg = 4 feet

hypotenuse = ?

Let "c" be the feet of wire needed

By pythogoras theorem for right angles triangle,

Therefore,

This means each wire will be 5 feet long

There are 3 wires per tree, which gives us 5 x 3 = 15 feet

There are 6 tree, so this is 15 x 6 = 90 feet of wire

Thus 90 feet of wire is needed for 6 trees

i think the answer is b

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -