The diagonal of a TV is 30 inches long. Assuming that this diagonal forms a pair of 30-60-90 right triangles, what are the exact length and width of the TV?. A. 15 inches by 15/3 inches. B. 15/2 inches by 15/2 inches . C. 60 inches by 60/3 inches . D. 60/2 inches by 60/2 inches
A, because in the 30 60 90 method the width is half of the diagonal and the only answer with 15 as the width is A
Let
x-------> the length of the rectangle
y------> the width of the rectangle
d----> the diagonal of the rectangle
we know that
The diagonal forms a pair of 30-60-90 right triangles
Step 1
Find the value of y
\(sin(30)=\frac{y}{d}\)
Solve for y
\(y=sin(30)*d\)
we have
\(sin(30)=\frac{1}{2}\\\\d=30\ in\)
substitute
\(y=\frac{1}{2} *30=15\ in\)
Step 2
Find the value of x
\(cos(30)=\frac{x}{d}\)
Solve for x
\(x=cos(30)*d\)
we have
\(cos(30)=\frac{\sqrt{3}}{2}\\\\d=30\ in\)
substitute
\(x=\frac{\sqrt{3}}{2}*30=15\sqrt{3}\ in\)
therefore
the answer is
\(15\ inches\) by \(15\sqrt{3}\ inches\)