# Video: KS2-M16 • Paper 3 • Question 18

The diagonals of this quadrilateral cross at right angles. Tick all the quadrilaterals that have diagonals which cross at right angles.

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### Video Transcript

The diagonals of this quadrilateral cross at right angles. Tick all the quadrilaterals that have diagonals which cross at right angles.

The blue lines show the diagonals of our first quadrilateral. Its diagonals cross at right angles. If we draw the diagonals on each of the quadrilaterals, we can see which diagonals cross at right angles. These diagonals do cross at right angles. So we need to tick this quadrilateral. These diagonals don’t cross at right angles. Both of the angles which I’ve marked in orange are obtuse or greater than 90 degrees.

We can also tick this quadrilateral. Its diagonals cross at right angles. These angles are obtuse. So the diagonals of our final quadrilateral do not cross at right angles. We’ve ticked these two quadrilaterals because their diagonals cross at right angles.