A given angle measures 90°.. Then, note that the total measurement of the triangle is 180°... Subtract 180° by 90°, and the other angles must add up to 90°!
Good luck!
The probability is 3/6 (1/2) as there are 3 prime numbers on a dice (2,3,5) and also 3 odd numbers on a dice (1,3,5)
18.8333333333is the answer
Start by putting two coins on each side of the scale. If one side is higher, then the light coin must be in that pair (use a second weighing to determine which of that pair is the lightest.)
If the initial weighing shows the two pairs to be even, discard those four and go to the three others. Put two of the coins on the scale - one on each side. If one side stays higher, that coin is your light one. If however they are equal, the final unweighed coin must be the lighter coin.