Answer:
c. 12x; 111 cm
Step-by-step explanation:
The regular dodecagon has 12 sides. Each side has a length of x=9.25 cm, and we know that the perimeter of the figure is the sum of the lengths of all the sides: Therefore, since we have 12 sides, the perimeter will be given by the product between the length of each side, x, and the number of sides, 12:
and if we substitute x = 9.25 cm, we find
Answer: k = -1 +/- √769
<u>Step-by-step explanation:</u>
48x - ky = 11
<u>-48x </u> <u> -48x</u>
-ky = -48x + 11
Slope:
*************************************************************************
(k + 2)x + 16y = -19
<u>- (k + 2)x </u> -<u>(k + 2)x </u>
16y = -(k + 2)x - 19
Slope:
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and
are perpendicular so they have opposite signs and are reciprocals of each other. When multiplied by its reciprocal, their product equals -1.
*
= -1
= 1
Cross multiply, then solve for the variable.
(k + 2)(k) = 16(48)
k² + 2k - 768 = 0
Use quadratic formula to solve:
k = -1 +/- √769