Question

△klm, lm=20 sqrt 3 m∠k=105°, m∠m=30° find: kl and km

Answer 1

Answer:

KL =  $\frac{20\sqrt{6}}{1+\sqrt{3}}$ = 17.93

MK =  $\frac{40\sqrt{3}}{1+\sqrt{3}}$ = 25.36

Explanation:

According to the Law of Sines:

$\frac{a}{sinA}=\frac{b}{sinB}= \frac{c}{sinC}$

where:

A, B, and C are angles

a, b, and c are the sides opposite to the angles

First of all, let's find m∠L: the sum of the angles of a triangle is 180°, therefore

m∠K + m∠L + m∠M = 180°

m∠L = 180° - m∠K - m∠M

m∠L = 180° - 105° - 30°

m∠L = 45°

Now, we can apply the Law of Sines to our case (see picture attached):

$\frac{LM}{sinK}=\frac{MK}{sinL}=\frac{KL}{sinM}$

Let's solve one side at the time:

$\frac{LM}{sinK}=\frac{MK}{sinL}$

$\frac{20\sqrt{3}}{sin(105)}=\frac{MK}{sin(45)}$

$MK = \frac{20\sqrt{3} }{sin(105)} \cdot sin(45)$

MK = $\frac{40\sqrt{3} }{1+\sqrt{3} }$ = 25.36

Similarily:

$\frac{LM}{sinK}=\frac{KL}{sinM}$

$\frac{20\sqrt{3}}{sin(105)}=\frac{KL}{sin(30)}$

$KL = \frac{20\sqrt{3} }{sin(105)} \cdot sin(30)$

KL = $\frac{20\sqrt{6}}{1+\sqrt{3}}$ = 17.93