Answer:
the second choice
Step-by-step explanation:
<u>Prove that:</u>

<u>Proof: </u>
We know that, by Law of Cosines,
<u>Taking</u><u> </u><u>LHS</u>
<em>Substituting</em> the value of <em>cos A, cos B and cos C,</em>



<em>On combining the fractions,</em>

<em>Regrouping the terms,</em>



LHS = RHS proved.
Area of a circle = pir^2
The radius is half the diameter so is 2 metres
So r^2 is 4
So the answer is 4pi or 12.57 metres squared
Let me know if you have any questions
Answer:
8.5 cm
Step-by-step explanation:
Angles of the triangle:
Right triangle as it has 90° angle
Sides are a, b and 19 cm
- sin 30°= a/19 ⇒ a= 19 sin 30°= 19*0.5= 8.5 cm = shortest side
- sin 60°= b/19 ⇒ b= 19 sin 60°= 19*0.866= 16.45 cm
-2n + 9mn - 17np
All you do is simplify the equation by distributing and multiplying the 1/3n to each of the numbers.
Hope this helps!