# Problem of the Week Problem B Screen Size, Now and Then

Flat screen TVs usually have a screen ratio of $$16:9$$. This means that if the screen is $$16$$ units wide, then it will be $$9$$ units high. If the screen is $$32$$ units wide, then since $$32 = 16\times 2$$, it will be $$9\times 2 = 18$$ units high, and so on.

1. Starting in the bottom-left corner of a grid that is $$20$$ units wide and $$10$$ units high, use a ruler to draw a flat screen TV screen that is $$16$$ units wide and $$9$$ units high.

2. Older TVs had a screen ratio of $$4:3$$. If an older TV was $$9$$ units high, how many units wide would it be?

3. Draw the TV screen from part (b) on the same grid used in part (a), also starting in the bottom-left corner.

4. How many more square units of area does the flat screen TV screen have compared to the older TV screen, if they both have a height of $$9$$ units?

5. A 4K flat screen TV has $$3840\times 2160$$ pixels. If the screen is $$122$$ cm wide by $$69$$ cm high, how many pixels per cm$$^2$$ are there? Round to the nearest whole number.

Themes: Geometry, Number Sense