7 × 100
+ 0 × 10
+ 6 × 1
0 x 0.1 1/10
+ 3 × 0.01 1/100
+ 9 × 0.001 1/1000
The fact that the coefficients are pairwise identical (except for sign) tells you that x^2 -1 is a factor (and x-5 is the other factor). Of course, you recognize x^2-1 as a special form (the difference of squares) that is factored as (x +1)(x -1).
The zeros are x = -1, +1, +5.
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A graphing calculator confirms this.
The circumference is found by multiplying the radius by pi by 2
And then the arc length would be multiplied by the fraction of the circle..
So using what you wrote is correct, but the answer you got is incorrect.
2x 3.14 x 90 = 565.2 meters
565.2 x 90/360 = 141.3 meters