A rhombus is a parallelogram with four equal-length sides. A square is a rectangle with four equal-length sides.

Parallel lines are lines that share the same slope (steepness) and therefore never intersect. A transversal occurs when a set of parallel lines are crossed by another line. All of the angles formed by a transversal are called interior angles and angles in the same position on different parallel lines equal each other (a° = w°, b° = x°, c° = z°, d° = y°) and are called corresponding angles. Alternate interior angles are equal (a° = z°, b° = y°, c° = w°, d° = x°) and all acute angles (a° = c° = w° = z°) and all obtuse angles (b° = d° = x° = y°) equal each other. Same-side interior angles are supplementary and add up to 180° (e.g. a° + d° = 180°, d° + c° = 180°).

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

c + x = 1
x = 1 - c

then substitute the result (1 - 1c) into the second equation:

c + 2(1 - c) = 4
c + (2 x 1) + (2 x -c) = 4
c + 2 - 2c = 4
c - 2c = 4 - 2
-c = 2
c = \( \frac{2}{-1} \)
c = -2

To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.

5a - 8a = -3a

The area of a rectangle is equal to its length x width:

a = l x w
a = a x b
a = 7 x 8
a = 56