Question

Do as directed.
1. The measure of three angles of a quadrilateral is 30°, 70° and 100". Find out (1)
the measurement of fourth angle.
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Answer 1

Answer:

Consider a quadrilateral, ABCD.

Let:

angle A = 30°.

angle B = 70°.

angle C = 100°.

Let, angle D, be the fourth angle.

Sum of all angles of a quadrilateral = 360°.

That is,

angle A + angle B + angle C + angle D = 360°.

Substituting the given values, we get,

30° + 70° + 100° + (angle D) = 360°.

200° + (angle D) = 360°.

angle D = 360° - 200° = 160°.

Therefore,

Measure of the fourth angle = 160°.