Law of cosines: a2 = b2 + c2 – 2bccos(A) Find the measure of J, the smallest angle in a triangle with sides measuring 11, 13, and 19. Round to the nearest whole degree. 30° 34° 42° 47°

Respuesta :

The smallest angle occurs opposite the shortest side length of the triangle. So by the law of cosines we have

[tex]11^2=13^3+19^2-2\cdot13\cdot19\cos\angle J\implies\cos\angle J=\dfrac{409}{494}\implies\theta\approx\boxed{34^\circ}[/tex]

Answer:

The measure of angle J is 34°

Step-by-step explanation:

Given,

J is the smallest angle in the triangle with sides measuring 11, 13, and 19,

Thus, J must be the opposite angle of the side measuring 11,

Since, the law of cosines,

[tex]a^2 = b^2 + c^2 - 2bc cos A[/tex]

Where, a, b and c are the sides of a triangle ABC,

Such that angle A is opposite to the side measuring a,

By applying the law,

We can write,

[tex]11^2 = 13^2 + 19^2 - 2\times 13\times 19 cos J[/tex]

[tex]121 = 169 + 361 - 494 cos J[/tex]

[tex]\implies cos J = \frac{169+361-121}{494}=\frac{409}{494}[/tex]

[tex]\implies m\angle J=34.1127839945\approx 34^{\circ}[/tex]

Second option is correct.