A quadrilateral has 3 angles measuring 59°, 129° and 78°. What does the missing angle measure?

1 answer

To find the missing angle in a quadrilateral, we need to use the fact that the sum of the angles in a quadrilateral is always 360°.

Let's denote the missing angle as x.

Given that the three known angles are 59°, 129°, and 78°, we can write an equation for the sum of all four angles:

59° + 129° + 78° + x = 360°

Simplifying the equation:

266° + x = 360°

Subtracting 266° from both sides of the equation:

x = 360° - 266°

x = 94°

Therefore, the missing angle measures 94°.