An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite:

d° = b° + c°

To find angle c, remember that the sum of the interior angles of a triangle is 180°:

180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 70° - 21° = 89°

So, d° = 21° + 89° = 110°

A shortcut to get this answer is to remember that angles around a line add up to 180°:

a° + d° = 180°
d° = 180° - a°
d° = 180° - 70° = 110°

To solve this equation, isolate the variable for which you are solving (b) on one side of the equation and put everything else on the other side.

-3b - 4z = b + 3z - 6
-3b = b + 3z - 6 + 4z
-3b - b = 3z - 6 + 4z
-4b = 7z - 6
b = \( \frac{7z - 6}{-4} \)
b = \( \frac{7z}{-4} \) + \( \frac{-6}{-4} \)
b = -1\(\frac{3}{4}\)z + 1\(\frac{1}{2}\)

A quadrilateral is a shape with four sides. The perimeter of a quadrilateral is the sum of the lengths of its four sides.

To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

6c(c - z)
6(8)(8 - 4)
6(8)(4)
(48)(4)
192

A monomial contains one term, a binomial contains two terms, and a polynomial contains more than two terms.