Mario broke a pane of glass in a window.The opening measured 7 and 1/4 inches by 9 and 1/2 in.At the hardware store,they sold him a pane of glass that was 7 and 1/4 inches by 9 and 1/2 inches to the nearest 1/4 inches.Can Mario be sure the glass will fit the window?And why

3 answers

yes
No. The glass measures to the nearest quarter of an inch, which means the measurements could be as much as 1/8 inch too big or two small in each directions.
No. Without a zero tolerance for larger dimensions, it could be larger than the opening. A clearance (smaller size) with a zero tolerance above 7 1/8 by 9 3/8 should have been specified.

Hardware stores should be able to provide +/- 1/8" tolerance (maximum error) on cut glass.