Question

IS ANYONE GOOD IN LAW OF COSINES..If so ill give brainlest​

Answer 1

Answer:

$X=70.5^o$

Step-by-step explanation:

we know that

The formula of the law of cosines is equal to

$c^2=a^2+b^2-2(a)(b)cos(C)$

where

a, b and c are sides. C is the angle opposite side c

In this context

The formula to calculate the measure of angle X is equal to

$YZ^2=XZ^2+XY^2-2(XZ)(XY)cos(X)$

substitute the given values

$22^2=20^2+18^2-2(20)(18)cos(X)$

solve for cos(X)

$484=400+324-(720)cos(X)$

$484=724-(720)cos(X)$

$(720)cos(X)=724-484$

$(720)cos(X)=240$

$cos(X)=240/720$

$X=cos^{-1}(240/720)=70.5^o$