Question

Round your answer to the nearest hundredth.. B ? 5 2 A С

Answer 1

Answer: m<B = 66.42

Step-by-step explanation:

Use cosine to find the missing angle.

Cosine = adjacent/hypotenuse

cos x = 2/5

since you know the side lengths and you’re finding the angle, use inverse cosine

cos -1 (2/5) = 66.4218215...

m<B = 66.42

Answer 2

Hey there!

We are looking for an angle. Whenever we want to look for an angle in a right triangle given two sides, we use inverse trigonometric functions. This is basically the inverse operation of the sine, cosine, and tangent. You could use it to undo any of these in an equation. If you said that the sine of x was equal to 1/2, you would do the inverse sine of 1/2 and get that x=30.

In our case, we see that the cosine of our angle is 2/5. How do we know that?

Well, we can remember the trigonometric functions using the mnemonic "soh cah toa"

SOH

Sine= Opposite/Hypotenuse

CAH

Cosine= Adjacent/Hypotenuse

TOA

Tangent= Opposite/Adjacent

If we look at the number values we have, we have 2 (the adjacent side to the angle) and 5 (the hypotenuse). This is adjacent over hypotenuse, which is the cosine. So, the cosine of our angle is 2/5.

Now, we can put this into an equation. I will call the measure of our mystery angle Θ (theta).

cosΘ= 2/5

We want to get the theta by itself to solve the equation. To do this, we have to use the inverse cosine on both sides of the equation to cancel out our cosine and figure out the value of theta. The inverse trig functions can be found on a calculator :)

cos$^-1$cosΘ=cos$^-1$ 2/5

Θ ≈ 66.42

I hope that this helps! Now you will be able to find any angle given two sides of a right triangle! Have a wonderful day!