Question

A quadrilateral has three angles that measure 90o , 100o, and 120o. which is the measure of the fourth angle?

Answer 1

The Interior Angles of a Quadrilateral add up to 360°, so:
the measure of the fourth angle = 360 - 90 - 100 - 120 = 50°

Answer 2

Answer: The measure of the fourth angle of the given quadrilateral is 50°.

Step-by-step explanation: Given that a quadrilateral has three angles that measure 90° , 100° and 120°.

We are to find the measure of the fourth angle of the quadrilateral.

Let x° be the measure of the fourth angle of the quadrilateral.

We know that

The sum of the measures of the four angles of a quadrilateral is 360°.

So, for the given quadrilateral, we have

`90^\circ+100^\circ+120^\circ+x^\circ=360^\circ\\\\\Rightarrow 310^\circ+x^\circ=360^\circ\\\\\Rightarrow x^\circ=360^\circ-310^\circ\\\\\Rightarrow x^\circ=50^\circ.`

Thus, the measure of the fourth angle of the given quadrilateral is 50°.