asked 80.2k views
2 votes
In △PQR,q=420 inches, p=400 inches and ∠P=64∘. Find all possible values of ∠Q, to the nearest degree.

2 Answers

3 votes

Final answer:

To find the possible values of ∠Q, apply the Law of Sines to triangle PQR using the given side lengths and angle. Calculate sinQ and then determine ∠Q, considering both acute and obtuse triangle possibilities.

Step-by-step explanation:

To find the possible values of ∠Q in △PQR, we can use the Law of Sines, which states that the ratio of the length of a side to the sine of its opposite angle is the same for all sides and angles in the triangle. The Law of Sines formula is α/sinA = β/sinB = γ/sinC, where α, β, and γ are the side lengths and A, B, and C are the respective opposite angles.

Given side p = 400 inches, side q = 420 inches, and angle ∠P = 64°, we apply the Law of Sines:

sinQ/q = sinP/p

sinQ/420 = sin(64°)/400

sinQ = (sin(64°)/400) × 420

Calculate the value of sinQ and then use the inverse sine function to find the angle measure of ∠Q. As the triangle could be acute or obtuse, consider both cases.

answered
User Andrew Davis
by
8.1k points
4 votes

The two possible values of angle Q to the nearest degree are
\(70^\circ\) and \(110^\circ\).

In triangle PQR, we are given:

q = 420 inches (side opposite angle Q)

p = 400 inches (side opposite angle P)


\(\angle P = 64^\circ\)

We can use the Law of Sines to find angle Q:


\[(\sin Q)/(q) = (\sin P)/(p)\]

First, find sin P:


\[\sin 64^\circ \approx 0.8988\]

Now, rearrange the Law of Sines equation to solve for sin Q:


\[\sin Q = (q * \sin P)/(p)\]


\[\sin Q = (420 * 0.8988)/(400)\]


\[\sin Q \approx 0.9411\]

Now, find the possible values of angle Q:


\[Q = \sin^(-1)(0.9411)\]


\[Q \approx 70.02^\circ\]

Remember, the Law of Sines gives us two possible angles for Q due to the ambiguity of the sine function. Since angle Q is in a triangle, the sum of angles in a triangle is
\(180^\circ\).

Therefore, to find the other possible value of angle Q, subtract the obtained value from
\(180^\circ\):

Second possible value:


\[Q = 180^\circ - 70.02^\circ\]


\[Q \approx 109.98^\circ\]

answered
User Trafalgarx
by
8.1k points
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