The measures of three angles of a quadrilateral are 80, 90, and 103 degrees. Find the measure of the fourth angle.
67
77
87
97

Question

The measures of three angles of a quadrilateral are 80, 90, and 103 degrees. Find the measure of the fourth angle.
67
77
87
97

lgbasallote · Answer

the total of angles of quadrilaterals is $360^o$ does that help?

anonymous · Answer

Angles have to add up to 360 no?

anonymous · Answer

360 = 80 + 90 + 103 + x <---- solve for x

anonymous · Answer

ok so 87

anonymous · Answer

gotchu

anonymous · Answer

yup, remember you can always set up algebraic equations to solve for any unknown as long as you have some initial information (like that all angles add up to 360 for a parallelogram)

anonymous · Answer

thanks for the help

anonymous · Answer

since it's a quadrilateral.. its a given that the sum of all the angles is 360

so add all the angles then subtract it from 360

$$360 - (80 + 90 +103 ) = 87$$
the measure of the fourth angle is   87  degrees.