You can't
Put a small pentagon inside a larger pentagon...
2 quarters, 4 dimes and 3 pennies.2 quarters, 4 dimes and 3 pennies.2 quarters, 4 dimes and 3 pennies.2 quarters, 4 dimes and 3 pennies.
1 quarter and 4 pennies is the best but there is also 29 pennies, 5 nickels and 4 pennies, 2 dimes a nickel and 4 pennies, 2 dimes and 9 pennies, 1 dime and 19 pennies, 1 dime 2 nickels and 9 pennies, 1 dime 1 nickel and 14 pennies, etc
2 dimeand 2 pennies
You can't
5 pennies in 3 rows, with a remainder of 4
Put a small pentagon inside a larger pentagon...
2 quarters, 4 dimes and 3 pennies.2 quarters, 4 dimes and 3 pennies.2 quarters, 4 dimes and 3 pennies.2 quarters, 4 dimes and 3 pennies.
1 quarter and 4 pennies is the best but there is also 29 pennies, 5 nickels and 4 pennies, 2 dimes a nickel and 4 pennies, 2 dimes and 9 pennies, 1 dime and 19 pennies, 1 dime 2 nickels and 9 pennies, 1 dime 1 nickel and 14 pennies, etc
2 dimeand 2 pennies
26 shells, 3 rows -> 5 per row with 1 remaining 19 pennies, 5 rows -> 3 per row with 4 remaining 17 balloons, 7 rows -> 2 per row with 3 remaining
Put three down to form a triangle, and the fourth in the middle. Your three rows of two are therefore three lines going from the central coin, to each corner coin.
Draw a star and put a penny on every corner.
You can have 34 pennies, 6 nickels and 4 pennies, 5 nickels and 9 pennies, 4 nickles and 14 pennies, 3 nickles and 19 pennies, 2 nickles and 24 pennies, 1 nickel and 29 pennies, 1 quarter and 9 pennies, 1 quarter 1 nickel and 4 pennies, 3 dimes and 4 pennies, 2 dimes and 14 pennies, 1 dime and 24 pennies, 1 dime and 1 nickel and 19 epnnies, 1 dime and 2 nickles and 14 pennies, 1 dime and 3 nickels and 9 pennies, 1 dime and 4 nickles and 4 pennies, 2 dimes and 1 nickel and 9 pennies, 2 dimes and 2 nickels and 4 pennies. I am pretty sure that is all the combinations, I could be mistaken, if so I am sorry because of the repetitive nature I might have missed one.
50 pennies45 pennies, 1 nickel40 pennies, 2 nickels40 pennies, 1 dime35 pennies, 3 nickels35 pennies, 1 nickel, 1 dime30 pennies, 4 nickels30 pennies, 2 nickels, 1 dime30 pennies, 2 dimes25 pennies, 5 nickels25 pennies, 3 nickels, 1 dime25 pennies, 1 nickel, 2 dimes25 pennies, 1 quarter20 pennies, 6 nickels20 pennies, 4 nickels, 1 dime20 pennies, 2 nickels, 2 dimes20 pennies, 1 nickel, 1 quarter15 pennies, 7 nickels15 pennies, 5 nickels, 1 dime15 pennies, 3 nickels, 2 dimes15 pennies, 2 nickels, 1 quarter15 pennies, 1 nickel, 3 dimes10 pennies, 8 nickels10 pennies, 6 nickels, 1 dime10 pennies, 4 nickels, 2 dimes10 pennies, 3 nickels, 1 quarter10 pennies, 2 nickels, 3 dimes10 pennies, 1 nickel, 1 dime, 1 quarter10 pennies, 4 dimes5 pennies, 9 nickels5 pennies, 7 nickels, 1 dime5 pennies, 5 nickels, 2 dimes5 pennies, 4 nickels, 1 quarter5 pennies, 3 nickels, 3 dimes5 pennies, 2 nickels, 1 dime, 1 quarter5 pennies, 1 nickel, 4 dimes5 pennies, 2 dimes, 1 quarter10 nickels8 nickels, 1 dime6 nickels, 2 dimes5 nickels, 1 quarter4 nickels, 3 dimes3 nickels, 1 dime, 1 quarter2 nickels, 4 dimes1 nickel, 2 dimes, 1 quarter5 dimes2 quarters1 half dollar
Having the same number of students in each row, 80 students can be arranged in 80 rows of 1, 40 rows of 2, 20 rows of 4, 10 rows of 8, and 5 rows of 16.