A really big one that is larger that the acute angel
-- After dog ate 1/2 of the collection, there were 29 remaining.
-- Just before dog came along, there were (2 x 29) = 58 cards.
-- That was after Dan added 5 new ones.
-- Before he added the 5 new ones, there were (58 - 5) = 53 cards.
-- When this story began, Dan had <em>53 cards</em>.
The triangle was just flipped so the missing side is going to equal 36, so...
2y+20= 36
(Subtract 20 from each side to isolate the 2y)
2y= 16
(Divide each side by 2 to isolate the variable)
ANSWER:
y= 8
