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

The equation of a circle is
(x-h)² + (y-k)² = r²
for center (h, k) and radius r. Of course, the radius can be computed by putting the point in the equation.
(x-2)² + (y-3)² = (-1-2)² + (1-3)² = 9+4 = 13
The standard equation of the circle is (x-2)² + (y-3)² = 13.
(5,12,13) is a right triangle and can be constructed.
All the others do not satisfy the triangle inequality, i.e. the sum of two short sides must exceed the long side in order for the triangle to be constructed.
Examples:
2+11<15, so no
3+7<11, so no
4+8<15, so no
but 5+12>13 so yes, it can be constructed.
Answer/Step-by-step Explanation:
Given:
a = no. of DVDs
b = no. of CDs
Total cost ($) for DVDs and CDs = 
a. The cost for 1 DVD = 2.5(a) = 2.5(1) = $2.5
The cost for 1 CD = 2(b) = 2(1) = $2
b. Total cost for 4 DVDs and 4 CDs:
Substitute a = 4, and b = 4 into the equation.


Total cost for 4 DVDs and 4 CDs = $18
c. To find out if $20 would be enough to buy 6 DVDs and 3 CDs, substitute a = 6, and b = 3 into the equation. Solve for the total cost to see if it equals $20 or is less than $20. If it's greater than $20, then it won't be enough.


6 DVDs and 3 CDs cost more than $20, therefore, $20 is not enough.
I believe the answer is false.
explanation: a special triangle has side lengths of 3-4-5 or 6-8-10. In this case since you have 10 one of the other sides would have to be 6 or 8. You can use pythagorean theorem.