Question

1. x =

119°
117°
125°
145°
133°
140°
x°

Explanation:

Step1: Recall sum - of - interior - angles formula

The sum of interior angles of an $n$-sided polygon is given by $(n - 2)\times180^{\circ}$. Here, $n = 7$, so the sum is $(7 - 2)\times180^{\circ}=900^{\circ}$.

Step2: Set up an equation

Let the unknown angle be $x$. Then $125 + 119+117 + 145+133+140+x=900$.

Step3: Simplify the left - hand side

$(125 + 119+117 + 145+133+140)+x=900$.
$789 + x=900$.

Step4: Solve for $x$

$x=900 - 789$.
$x = 111$.

Answer:

$111$