High School

Triangle ABC has the following measures:

- [tex]m\angle A = 46^\circ[/tex]
- [tex]m\angle B = 73^\circ[/tex]
- [tex]b = 32.3[/tex]

What is the length of side [tex]c[/tex]?

A. 29.5
B. 35.9
C. 61.0
D. 24.3

Answer :

We are given a triangle with

- [tex]$A = 46°$[/tex],
- [tex]$B = 73°$[/tex], and
- side [tex]$b = 32.3$[/tex].

Step 1. Find Angle [tex]$C$[/tex]

Since the sum of the angles in a triangle is [tex]$180°$[/tex], we have

[tex]$$
C = 180° - A - B = 180° - 46° - 73° = 61°.
$$[/tex]

Step 2. Apply the Law of Sines

The Law of Sines states that

[tex]$$
\frac{a}{\sin(A)} = \frac{b}{\sin(B)} = \frac{c}{\sin(C)}.
$$[/tex]

We want to find side [tex]$c$[/tex]. Using the relation between [tex]$b$[/tex] and [tex]$c$[/tex], we have

[tex]$$
\frac{b}{\sin(B)} = \frac{c}{\sin(C)}.
$$[/tex]

So, solving for [tex]$c$[/tex] gives

[tex]$$
c = \frac{\sin(C)}{\sin(B)} \cdot b.
$$[/tex]

Step 3. Substitute the Known Values

Substitute [tex]$b = 32.3$[/tex], [tex]$\sin(C)$[/tex] with [tex]$C = 61°$[/tex], and [tex]$\sin(B)$[/tex] with [tex]$B = 73°$[/tex]. This yields

[tex]$$
c = \frac{\sin(61°)}{\sin(73°)} \cdot 32.3.
$$[/tex]

Step 4. Compute the Value of [tex]$c$[/tex]

Evaluating the ratio of sines and then multiplying by [tex]$32.3$[/tex], we obtain a value of approximately

[tex]$$
c \approx 29.54.
$$[/tex]

Rounding this to one decimal place, the length of side [tex]$c$[/tex] is

[tex]$$
c \approx 29.5.
$$[/tex]

Thus, the length of side [tex]$c$[/tex] is [tex]$\boxed{29.5}$[/tex].

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