Question

Calculate the size of angle x.
x
240°
x
x

Answer 1

280 degrees.

Explanation:

The way you work this out is by:

1) Work out 240-360

2) Subtract the answer from 360

3) Divide the answer of step 2 into however many angles you have (in this instance 4).

4) Then use one of these angles and subtract it from 360. This will give you a reflex angle.

5) That's it.

Answer 2

• Angle x is 280°

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We know that the sum of interior angles of a quadrilateral is 360°.

Show this as a sum using angle measures in the diagram:

• 3(360 - x) + (360 - 240) = 360
• 3*360 - 3x + 120 = 360
• 360 - x + 40 = 120
• x = 400 - 120
• x = 280