3 years ago

Find the length of a.

Mathematics

2 answers:

denis-greek [22]3 years ago

8 0

The answer is 22.2 is correct

inessss [21]3 years ago

6 0

Answer:

22.2

Step-by-step explanation:

Using cosine rule,

$a^{2} = 12^{2} + 15^{2} -2(12)(15)cos110$ °

$a = \sqrt{12^{2} +15^{2}-2(12)(15)cos110 }$

$a = 22.2 (3 sf)$

You might be interested in

Prove that 1/sin^2A -1/tan^2A= 1

Vika [28.1K]

Answer:

Step-by-step explanation:

$LHS =\dfrac{1}{Sin^{2} \ A }-\dfrac{1}{Tan^{2} \ A }\\\\\\ = \dfrac{1}{sin^{2} \ A}- \dfrac{1}{\dfrac{Sin^{2} \ A}{Cos^{2} \ A}}\\\\\\= \dfrac{1}{sin^{2} \ A } - \dfrac{Cos^{2} \ A}{Sin^{2} \ A}\\\\\\= \dfrac{1-Cos^{2} \ A}{Sin^{2} \ A}\\\\\\= \dfrac{Sin^{2} \ A}{Sin^{2} \ A}\\\\\\= 1 = \ RHS$