Math help please.. number 13
1 answer:
Use the Law of Cosines here with angle A as your reference angle. It will be the one that the helicopter is at, the one we are looking for. If that angle is angle A, then the side across from it is a, measure of 11.4. Here's how the Law looks in our particular situation: 
. Simplifying a bit we get 129.96 = 54.76 + 72.25 - 125.8cos(A) Combining like terms across the equals sign gives us 2.95 = -125.8 cosA. Doing the division we get -.0234499205 = cosA. Find the angle using the 2nd and cos buttons on your calculator. It's 91.34°, rounded to just 91°. Choice A
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- Find x.
To solve these type of problems you need to use the pythagoras theorem ⇨ Hypotenuse² = Base² + Altitude².
Here,
- Altitude = 1.6 cm.
- Base = 1.2 cm
- Hypotenuse = x
Now, let's solve for x.
Hypotenuse² = Base² + Altitude²
x² = (1.2)² + (1.6)²
x² = 1.44 + 2.56
x² = 4
x = √4
x = <em><u>2</u></em><em><u>.</u></em>
- So, the value of x is <em><u>2</u><u> </u><u>cm.</u></em>
- Pythagoras theorem can be used only in the cases of right-angled triangles. Here, it's given that the triangle is right angled so we can use this theorem.
- To solve the squares if decimals, take them as whole numbers & then just add the decimal points. For example, ⇨ for (1.2)², take it as 12² , then multiply 12 by 12, you'll get 144. Now, add the decimal place accordingly ⇨ 1.44 . So, (1.2)² = 1.44.