Given:
In triangle OPQ, o = 700 cm, p = 840 cm and q=620 cm.
To find:
The measure of angle P.
Solution:
According to the Law of Cosines:
[tex]\cos A=\dfrac{b^2+c^2-a^2}{2bc}[/tex]
Using Law of Cosines in triangle OPQ, we get
[tex]\cos P=\dfrac{o^2+q^2-p^2}{2oq}[/tex]
[tex]\cos P=\dfrac{(700)^2+(620)^2-(840)^2}{2(700)(620)}[/tex]
[tex]\cos P=\dfrac{490000+384400-705600}{868000}[/tex]
[tex]\cos P=\dfrac{168800}{868000}[/tex]
On further simplification, we get
[tex]\cos P=0.19447[/tex]
[tex]P=\cos^{-1}(0.19447)[/tex]
[tex]P=78.786236[/tex]
[tex]P\approx 79[/tex]
Therefore, the measure of angle P is 79 degrees.
