Find the probability for one roll of a standard number cube. p(even or 3)

total possible numbers are 6

 there are 3 even numbers ( 2, 4, 6)

or a 3  so 4 total numbers to roll

 so you have  4/6 reduces to 2/3 probability

f

step-by-step explanation:

f

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4