Question

drawbridge at the entrance to an ancient castle is raised and lowered by a pair of chains. The figure represents the drawbridge when flat. Find the height of the suspension point of the chain, to the nearest tenth of a meter, and the measures of the acute angles the chain makes with the wall and the drawbridge, to the nearest degree.

Answer 1

Answer:

4.0 meters, ∠C = 39°, ∠A = 51°

Step-by-step explanation:

Firstly, our diagram shows us that the given triangle is actually a right triangle. So we can use the Pythagorean Theorem to solve for the height of the chain:

$a^{2} +b^{2} =c^{2}$

$(3.3)^{2} +b^{2} =(5.2)^{2}$

$b^{2} =(5.2)^{2}-(3.3)^{2}$

$b =\sqrt{(5.2)^{2}-(3.3)^{2}}$

$b=4.0187...$

$b=4.0 m$

Now, we can use the Law of Cosines to figure out one of the acute angles:

$c^{2} =a^{2} +b^{2} -2ab(cos(C))$

$(3.3)^{2} =(4.0)^{2} +(5.2)^{2} -2(4.0)(5.2)(cos(C))$

$cos(C)=\frac{(3.3)^{2}-(4.0)^{2} -(5.2)^{2}}{-2(4.0)(5.2)}$

$C=cos^{-1}( \frac{(3.3)^{2}-(4.0)^{2} -(5.2)^{2}}{-2(4.0)(5.2)})$

$C=39.3915...$

∠C = 39°

And since we know that all angles in a triangle add up to 180°:

∠A + ∠B + ∠C = 180

∠A + 90 + 39 = 180

∠A = 180 - 90 - 39

∠A = 51°

However, you should always review any answers on the Internet and make sure they are correct! Check my work to see if I made any mistakes!