Answer:
Option D = 16π/3 ft
Step-by-step explanation:
Arc length formula is written Mathematically as:
Arc length = 2πr × θ /360
r = 4 ft
θ = Central angle in degrees = 240°
2 × π × 4 × 240/360
8π × 240/360
8π × 20/30
16π/3 ft
So, the arc length is 16π/3 ft
91.5 is the perimeter. It's just 5a.
Answer:

Step-by-step explanation:
From the question we are told that
System of equations given as
x₁ + 3x₂ + x₃ + x₄ = 3;
2x₁ - 2x₂ + x₃ + 2x₄ = 8;
x₁ - 5x₂ + x₄ = 5
Matrix form

Generally the echelon reduction is mathematically applied as

Add -2 times the 1st row to the 2nd row

Multiply the 2nd row by -1/8

Add -1 times the 2nd row to the 3rd row

Multiply the 3rd row by -8/41

Add -1/8 times the 3rd row to the 2nd row
Add -1 times the 3rd row to the 1st row

Add -3 times the 2nd row to the 1st row
