Find the measure of Q, the smallest angle in the triangle whose sides have lengths 4-5, and 6. Round the measure to the nearest whole degree.
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Given:
Given that PQR is a triangle.
The measures of the sides of the triangle are 4,5 and 6.
We need to determine the measure of ∠Q.
Measure of ∠Q:
The measure of ∠Q can be determined using the law of cosines formula.
Thus, we have;
[tex]\cos (Q)=\frac{p^{2}+r^{2}-q^{2}}{2 p r}[/tex]
Substituting p = 6, q = 4, r = 5, we get;
[tex]\cos (Q)=\frac{6^{2}+5^{2}-4^{2}}{2 (6)(5)}[/tex]
Simplifying, we get;
[tex]\cos (Q)=\frac{36+25-16}{2 (30)}[/tex]
[tex]\cos (Q)=\frac{45}{60}[/tex]
Dividing, we get;
[tex]\cos (Q)=0.75[/tex]
[tex]Q=cos^{-1}(0.75)[/tex]
[tex]Q=41^{\circ}[/tex]
Thus, the measure of ∠Q is 41°
Hence, Option b is the correct answer.