Chan hee bought 3.4 pounds of coffee that cost $6.95 per pound how much did he spend on coffee

The angle of elevation of the top of a pole as seen from a point 13 ft away from the base is double its angle of elevation as se

spayn [35]

The height of the pole above the level of the observer's eyes is 31.42 ft

Let the angle of elevation of the top of the pole from a point 47 ft away be α.

Let the angle of elevation of the top of the pole from the point 13 ft away be β.

Since the angle of elevation of a point 13 feet away is twice that from 47 ft away, we have that β = 2α.

If the height of the pole above the level of the observer's eye is h, we have that

tanβ = tan2α = h/13 and tanα = h/47

From trigonometric identities tan2α = 2tanα/(1 - tan²α)

Substituting the values of the variables into the equation, we have

tan2α = 2tanα/(1 - tan²α)

h/13 = 2h/47 ÷ [1 - (h/47)²]

Dividing through by h, we have

1/13 = 2/47 ÷ [1 - (h/47)²]

Cross-multiplying, we have

1/13 = 2/47 ÷ [1 - (h/47)²]

1 - (h/47)² = 2/47 × 13

1 - (h/47)² = 26/47

(h/47)² = 1 - 26/47

(h/47)² = (47 - 26)/47

(h/47)² = 21/47

Taking square-root of both sides, we have

h/47 = √(21/47)

Cross-multiplyng, we have

h = √(21/47) × 47

h = √(21 × 47)

h = √987

h = 31.42 ft

The height of the pole above the level of the observer's eyes is 31.42 ft

Learn more about height of a pole here:

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4 0

2 years ago

The radius of a clock face is 8.5 centimeters. what is circumfe0rence of clock?

kondor19780726 [428]

Answer:

The circumference of clock is, 53.38 cm

Step-by-step explanation:

Circumference(C) of the circle is given by:

$C = 2 \pi r$ ....[1]

where, r is the radius of the circle.

As per the statement:

the radius of a clock face is 8.5 centimeters

⇒r = 8.5 cm

Use $\pi = 3.14$

Substitute the given values in [1] we have;

$C = 2 \cdot 3.14 \cdot 8.5$

Simplify:

C = 53.38 cm

Therefore, the circumference of clock is, 53.38 cm

7 0

2 years ago

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What is 15/22 as a repeating decimal?

andrew11 [14]

Answer:

0.6818

Step-by-step explanation:

6 0

3 years ago

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How to convert ounces into pounds?

Vesna [10]

Hello! Its really simple 16 ounces equal 1 pound!

8 0

3 years ago

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Evaluate C= 2 A r, for r= 8.<br>C=10,<br>C = 16<br>C= 28.7<br>C= 16

USPshnik [31]

Answer: Second Option

$C = 16\pi$

Step-by-step explanation:

We are evaluating aarco lengths

The formula for the arc length is:

$C = 2\pi r$

We want to know what is the arc length for a radius of r = 8

Then we substitute r = 8 in the equation and solve

$C = 2 \pi * 8$

$C = 16\pi$

The correct answer is the second option

8 0

3 years ago

Read 2 more answers