What is the value of x?

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2 Answers
Oct 2, 2016

Seventh angle is x=111^o

Explanation:

Sum of all the interior angles of a n-sided polygon is always (n-2)xx180^o.

As this is seven sided polygon, sum of its interior angles is (7-2)xx180^o=5xx180^o=900^o

Sum of six of the angles is 120^o +158^o +126^o +125^o +121^o +139^o =789^o

Hence the seventh angle is x=900^o-789^o=111^o

Oct 2, 2016

111^circ

Explanation:

We use the formula

The sum of the angles in any closed polygon

color(blue)((n-2)*180)

Where, color(red)(n is the number of sides of the polygon

There are 7 sides in this polygon

:. color(orange)("Sum of the angles"=(7-2)*180=900^circ

So, we can say that

rarr158^circ+120^circ+139^circ+121^circ+125^circ+126^circ+x=900^circ

rarr789^circ+x=900^circ

rarrx=900^circ-789^circ

rArrcolor(green)(x=111^circ