Question

Please help. i dont know what to do.​

Answer 1

Answer:

a wild guess would be...56/81

Step-by-step explanation:

This is only right if the triangle is rectangular !

First try to figure out what the length of the other side of the triangle is with the Pythagorean theorem (=> a^2 = b^2 + c^2).

<=> a^2 - c^2 = b^2

 => 9^2 - 5^2 = b^2

<=> 81 - 25 = b^2 = 56

therefor b = the square root of 56.

Next you try to figure out what the cosinus of that angle would be.

the square root of 56/9

Now must you multiply that by two;

112/9

Because this is not an option maybe we need to do something like;

(square root of 56/9)^2

that would equal

56/81

which is the last option.

I do not understand it very much myself so have fun trying to find the correct answer.