Angles in Quadrilaterals Flashcards

All 5 cards in this deck

What do the angles in a quadrilateral add up to?

$360^\circ$

How many triangles can any quadrilateral be split into, and what does that show about its angle sum?

$2$ triangles, so the angle sum is $2 \times 180 = 360^\circ$.

True or false? A kite's angles add up to less than $360^\circ$ because it is not a rectangle.

False. The angles of any quadrilateral add up to $360^\circ$.

What are the steps to find a missing angle in a quadrilateral, with a reason?

e.g. three angles are $100^\circ$, $80^\circ$ and $90^\circ$

1. Add the known angles: $100 + 80 + 90 = 270$
2. Subtract from $360$: $360 - 270 = 90^\circ$
3. Reason: angles in a quadrilateral add up to $360^\circ$

What are the steps to find an angle outside a quadrilateral, on a straight line through one of its vertices?

e.g. three angles of the quadrilateral are $130^\circ$, $65^\circ$ and $95^\circ$, and the fourth vertex lies on a straight line with the angle $y$

1. Fourth interior angle: $360 - 130 - 65 - 95 = 70^\circ$ (angles in a quadrilateral add up to $360^\circ$)
2. $y = 180 - 70 = 110^\circ$ (angles on a straight line add up to $180^\circ$)