Question

HELP PLEASE

Answer 1

Answer:

26.4

Step-by-step explanation:

Law Of Cosines:

    $cos(A)=\frac{b^2+c^2-a^2}{2bc}$

    This should work for any side. This can generally be thought as:

   $cos(\text{angle}) = \frac{\text{sum of squares of two other sides-opposite side squared}}{\text{2 times the product of the other two sides}}$

    If this is too confusing here's the formula for the other sides (which is essentially the same, just different variables)

   $cos(B)=\frac{a^2+c^2-b^2}{2ac}$

   $cos(C) =\frac{a^2+b^2-c^2}{2ab}$

Anyways now just plug in the known values into the equation

$cos(A)=\frac{4^2+6^2-3^2}{2(6)(4)}$

Square and multiply values

$cos(A)=\frac{16+36-9}{48}$

Add the values in the numerator

$cos(A)=\frac{43}{48}$

Take the inverse of cosine on both sides

$A=cos^{-1}(\frac{43}{48})$

calculate arccosine (inverse cosine) using a calculator

$A\approx 26.384$

Round to nearest tenth

$A\approx26.4$