Does anyone know the answer to this ?!

 Yes.

The perimeter is about 42.86 m    Round to 42.9 m

The area is about 138.59 m² . Round to 138.6 m²

Explanation:

To find the perimeter, you need the length of the sides. Imagine the octagon as 8 isosceles triangles assembled. You need the length of the short (exterior) side to calculate the perimeter.

With only the length of the ray given, you could use some trig. A calculator is necessary!

The octagon has 8 sides, you can calculate the size of the central angle between two radii 360/8 = 45.  Subtract from 180 and divide by 2 to get the measure of one of the equal angles.

That angle measure is 67.5°  Use cos(67.5)(7) = 2.678784027 the length of half of the side-- between the dotted line and the ray in the diagram.

2(2.678784027)(8) = 42.86054443 is the perimeter.

The area of each isosceles triangle is bh/2.

Find the height by using sin(67.5)(7) = 6.467156728

The cos(67.5)(7) is already half the base. Use as is!

6.467156728 × 2.678784027 = 17.32411614

This is the area of 1 of the 8 imaginary triangles, so multiply by 8 for the whole area of the octagon.

17.32411614 × 8 = 138.5929291

I hope this helps. Complicated!

There may be easier ways, but this is the only way I know at this point.

the answer is not negative reinforcement.