A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r²h and the surface area is 2(π r²) + 2π rh.

The area of a trapezoid is one-half the sum of the lengths of the parallel sides multiplied by the height:

a = ½(b + d)(h)
a = ½(7 + 9)(3)
a = ½(16)(3)
a = ½(48) = \( \frac{48}{2} \)
a = 24

You need to find the value of c so solve the first equation in terms of z:

7c + z = 6
z = 6 - 7c

then substitute the result (6 - 7c) into the second equation:

3c + 2(6 - 7c) = 9
3c + (2 x 6) + (2 x -7c) = 9
3c + 12 - 14c = 9
3c - 14c = 9 - 12
-11c = -3
c = \( \frac{-3}{-11} \)
c = \(\frac{3}{11}\)

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

2c - 8 = -3 + c
2c = -3 + c + 8
2c - c = -3 + 8
c = 5