Question

Work out the value of X.

Answer 1

Those are supplementary angles, therefore:

$4x+5x=180\\9x=180\\x=20$

Answer 2

Answer:

• $x = 20 {}^ \circ$

Step-by-step explanation:

That are supplementary, means:

They add up to 180°.

Here is the same case.

Given angles are:

• 4x & 5x

Solved:

• $4x + 5x = 180 {}^ \circ$

Combining them,

• $9x = 180 {}^{ \circ}$

Transposing 9 to RHS,

• $x = \cfrac{ \cancel{180} \: {}^{20} }{ \cancel9}$

• $x = 20$

Hence, value of x is 20.