Lisa's penny bank is 1/10 full. after she adds 440 pennies, it is 3/5 full. how many pennies can lisa's bank hold?

Step-by-step explanation:

After the 440 pennies are added, the bank is 3/5 full.  It started out 1/10 full, so

3/5 - 1/10 is the amount of space in the bank that the 440 pennies took up, or

1/2.  Use proportions to solve this, with number of pennies on the top and the fraction of the bank that is filled on the bottom:

where x is the number of pennies (our unknown) that it will take to fill the bank (1).  Cross multiply to get

so x = 880

δabc ≅ δdcb by sas because

db ≅ ac . . given (side)

bc ≅ bc . . reflexive property (side)

∠dbc ≅ ∠ acb . . alternate interior angles where transversal bc crosses parallel lines bd and ac (included angle)