In △abc, m∠a=16°, m∠b=49°, and a=4. find c to the nearest tenth.
not a right triangle

c = 13.2

Step-by-step explanation:

* Lets explain how to solve the problem

- In Δ ABC

# Side a is opposite to ∠A

# Side b is opposite to ∠B

# Side c is opposite to ∠C

- The sine rule is:

#

* Lets solve the problem

- In Δ ABC

∵ m∠A = 16°

∵ m∠B = 49°

∵ The sum of the measures of the interior angles of a triangle is 180°

∴ m∠A + m∠B + m∠C = 180°

∴ 16° + 49° + m∠C = 180°

∴ 65° + m∠C = 180° ⇒ subtract 65° from both sides

∴ m∠C = 115°

- Lets use the sine rule to find c

∵ a = 4 and m∠A = 16°

∵ m∠C = 115°

∵

- By using cross multiplication

∴ c sin(16) = 4 sin(115) ⇒ divide both sides by sin(16)

∴

* c = 13.2

jml angle lkj & angle mj = lm