Amanda has a 2 cm rod, a 5 cm rod, and a 9 cm rod.  She will randomly chooes a fourth rod from a box containing rod of lengths 2, 4, 6, 8, 10, 12, 14, 16, 8, and 20 cm.  What is the probability that Amanda four rods will be able to form a convex quadrilateral, if the rods are to be connected endpoint to endpoint?

 Nov 19, 2019

Do you know what a convex quadrilateral is?  Perhaps you would like to share this knowledge with other forum users.?


Have you tried playing with a rough sketch. If so you will be able to discound some of the possibilies straight away.

Which ones can you discount straight away, and why?

 Nov 20, 2019
edited by Melody  Nov 20, 2019

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