Question

16

(x + 40)0 and (3x - 20)° are a pair of supplementary angles.
Find the following values:
X=
the smaller angle is :
0
and
the greater angle is :
0​

Answer 1

x = 40

smaller angle is 80

larger angle is 100

Explanation:

Supplementary angles add up to equal 180 degrees

Hence, x + 40 + 3x - 20 = 180

( note that we just created an equation that we can use to solve for x )

We now solve for x using the equation created

x + 40 + 3x - 20 = 180

step 1 combine like terms

x + 3x = 4x

40 - 20 = 20

we now have 4x + 20 = 180

step 2 subtract 20 from each side

180 - 20 = 160

we now have 160 = 4x

step 3 divide each side by 4

160 / 4 = 40

4x / 4 = x

we're left with x = 40

we now plug in 40 for x to find the value of each angle

x + 40

* substitute 40 for x *

40 + 40 = 80

3x - 20

* substitute 40 for x *

3 ( 40 ) - 20

3 * 40 = 120

120 - 20 = 20

so the larger angle is 100 degrees and the smaller angle is 80 degrees