Question

N triangle ABC, m∠A = 35° and m∠B = 40°, and a=9. Which equation should you solve to find b?

Answer 1

Answer:

The equation is 9/sin(35) = b/sin(40) , The length of b = 10.086

Step-by-step explanation:

* Lets explain how to solve the triangle

- In ΔABC

- a, b, c are the lengths of its 3 sides, where

# a is opposite to angle A

# b is opposite to angle B

# c is opposite to angle C

- m∠A = 35°  

- m∠B = 40°  

- a = 9  ⇒ the side opposite to angle A

* To solve the triangle we can use the sin Rule

- In any triangle the ratio between the length of each side  

 to the measure of each opposite angle are equal

- a/sinA = b/sinB = c/sinC

∴ The equation which used to find b is a/sinA = b/sinB  

∵ a = 9 , m∠A = 35° , m∠B = 40°

∴ 9/sin(35) = b/sin(40) ⇒ by using cross multiplication

∴ b = 9 × sin(40) ÷ sin(35) = 10.086

* The length of b = 10.086

Answer 2

Answer:

$\frac{sin B}{b} = \frac{sin A}{a}$ should be used to find b.

Step-by-step explanation:

We are given that in a triangle ABC, ∠A = 35°, ∠B = 40° and side a = 9 and we are to find the side length b.

Now using sine rule to find b:

$\frac{sin B}{b} = \frac{sin A}{a}$

$\frac{sin 40}{b} = \frac{sin 35}{9}$

$b=\frac{sin 40 \times 9}{sin 35}$

b = 10.1