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2 years ago

8

a 4 ft post casts a 20 inch shadow at the same time a nearby cell phone tower casts a 125 ft shadow. how tall is the cell phone

tower?

1 answer:

Natalka [10]2 years ago

4 0

Notice the picture below

so, the two triangles are similar by AA

thus $\bf \cfrac{x}{4}=\cfrac{125}{20}$ solve for "x"

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Yan buys tickets to a concert for himself and a friend there is tax of 6% on the price of the tickets and an additional booking

lyudmila [28]

X = price of the tickets (without tax)

1.06x + 20 <== ur expression

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3 years ago

How many times the size of 0.81 is 810

MAXImum [283]

Answer:

810 is 100 times the size of 0.81

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2 years ago

Calculating cos-1 ( help is gladly appreciated :) )

Alekssandra [29.7K]

Answer:

$\frac{3\pi}{4}$

(Assuming you want your answer in radians)

If you want the answer in degrees just multiply your answer in radians by $\frac{180^\circ}{\pi}$ giving you:

$\frac{3\pi}{4} \cdot \frac{180^\circ}{\pi}=\frac{3(180)}{4}=135^{\circ}$ .

We can do this since $\pi \text{ rad }=180^\circ$ (half the circumference of the unit circle is equivalent to 180 degree rotation).

Step-by-step explanation:

$\cos^{-1}(x)$ is going to output an angle measurement in $[0,\pi]$ .

So we are looking to solve the following equation in that interval:

$\cos(x)=-\frac{\sqrt{2}}{2}$ .

This happens in the second quadrant on the given interval.

The solution to the equation is $\frac{3\pi}{4}$ .

So we are saying that $\cos(\frac{3\pi}{4})=\frac{-\sqrt{2}}{2}$ implies $\cos^{-1}(\frac{-\sqrt{2}}{2})=\frac{3\pi}{4}$ since $\frac{3\pi}{4} \in [0,\pi]$ .

Answer is $\frac{3\pi}{4}$ .

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2 years ago

which of the following sets could be the sides of a right triangle? {2,3, square root 13} {5,5,2 square root 10} {5,12,15}

anastassius [24]

All of these sets meet the requirements of the triangle inequality. The sum of any two numbers in the set is greater than the third one. (You really only need to check that the sum of the smallest two is greater than the largest.)

It can help to resolve the numbers that are only indicated as to value.

√13 ≈ 3.606

2√10 ≈ 6.325

_____

Your comparisons can be ...

2 + 3 = 5 > 3.606 . . . is a triangle

5 + 5 = 10 > 6.325 . . . . . . is a triangle

5 + 12 = 17 > 15 . . . . . . . . is a triangle

8 0

3 years ago

Determine whether the function has a maximum or minimum value. <br> f(×)= x^2+9

PtichkaEL [24]

$f(x)= x^2+9\\\\for\ each\ x\in R\\\\x^2 \geq 0\ \ \ \Rightarrow\ \ \ x^2+9 \geq 9\ \ \ \Rightarrow\ \ \ f(x) \geq 9\\\\y_{min}=9\\ y_{max}\ \ \ \rightarrow\ \ \ not\ exist$

3 0

3 years ago

Read 2 more answers