Question

Need help fast plz for my pre calc exam

Answer 1

Answer:

h = 8.54 units

Step-by-step explanation:

The Law of Cosines

It relates the length of the sides of a triangle with one of its internal angles.

Let a,b, and c be the length of the sides of a given triangle, and x the included angle between sides a and b, then the following relation applies:

$c^2=a^2+b^2-2ab\cos x$

Since we know the values of all three side lengths, we solve the equation for x:

$\displaystyle \cos x=\frac{a^2+b^2-c^2}{2ab}$

For the triangle ABC in the image, a=10, b=15, c=13, thus:

$\displaystyle \cos A=\frac{10^2+15^2-13^2}{2*10*15}$

$\displaystyle \cos A=\frac{156}{300}$

$\displaystyle \cos A=0.52$

Thus, A = 58.67°

For the right triangle of height h and hypotenuse 10, we use the sine ratio:

$\displaystyle \sin 58.67^\circ=\frac{h}{10}$

Solving for h:

$h = 10\sin 58.67^\circ$

h = 8.54 units