Answer:
15 feet.
Step-by-step explanation:
A bulletin board has been shown in the figure below.
Where the width of the board AB = DC = [tex]4\frac{1}{2}[/tex] = 4.5 feet
and the length of the board AD = BC = 6 feet
As Ms. Berkin is dividing the board by stretching the ribbons to the opposite corners so the length of ribbons will be AC and BD.
In right angle triangle ADC, using Pythagorean Theorem,
[tex]AC^2=AD^2+DC^2[/tex] = [tex]6^2+4.5^2=36+20.25=56.25[/tex]
[tex]AC= \sqrt{56.25} = 7.5[/tex] feet
Similarly in triangle BDC,
[tex]BD^2=BC^2+DC^2 = 6^2+4.5^2=36+20.25 =56.25[/tex]
[tex]BD=\sqrt{56.25} = 7.5[/tex] feet
Thus, total length of the ribbon used = AC + BD = 7.5 + 7.5 = 15 feet
