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3 years ago

What is the area of triangle ABC?

Mathematics

1 answer:

Stella [2.4K]3 years ago

7 0

9514 1404 393

Answer:

C. 36√3 square units

Step-by-step explanation:

Your knowledge of special triangles tells you that height CD is ...

CD = 6√3

so the area is ...

A = 1/2bh

A = 1/2(12)(6√3) = 36√3 . . . . square units

_____

<em>Additional comment</em>

The 30°-60°-90° right triangle that is half an equilateral triangle has a short side equal to half the length of the long side. The Pythagorean theorem tells you that the middle-length side is √(2²-1²) = √3 times the shortest side. That is, the side length ratios in this "special" triangle are ...

1 : √3 : 2

This means the length DB is 12/2 = 6, and the length CD is 6√3.

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The angles of depression of two ships from the top of the light house are 45° and 30° towards east. If the ships are 200 m apart

azamat

Answer:

273 meters

Step-by-step explanation:

See image attached for the diagram I used to represent this scenario.

The distance between the ships, at angles 30 and 45, is 200 meters. The distance between the left ship and the lighthouse is x meters.

We can use trigonometric ratios to solve this problem. We can use the tangent ratio $\big{(} \frac{\text{opposite}}{\text{adjacent}} \big{)}$ to create an equation with the two angles.

$\displaystyle \text{tan(45)} = \frac{h}{x}$
$\displaystyle \text{tan(30)} = \frac{h}{x+200} }$

Let's take these two equations and solve for x in both of them.

<h2> $\textbf{Equation I}$ </h2>

$\displaystyle \text{tan(45)} = \frac{h}{x}$

tan(45) = 1, so we can rewrite this equation.

$\displaystyle 1=\frac{h}{x}$

Multiply x to both sides of the equation.

$\displaystyle x = h$

<h2> $\textbf{Equation II}$ </h2>

$\displaystyle \text{tan(30)} = \frac{h}{x+200} }$

Multiply x + 200 to both sides and divide h by tan(30).

$\displaystyle \text{x + 200} = \frac{h}{\text{tan (30)}}$

Subtract 200 from both sides of the equation.

$\displaystyle \text{x} = \frac{h}{\text{tan (30)}} - 200$

Simplify h/tan(30).

$x=\sqrt{3}h - 200$

<h2> $\textbf{Equation I = Equation II}$ </h2>

Take Equation I and Equation II and set them equal to each other.

$h=\sqrt{3}h-200$

Subtract √3 h from both sides of the equation.

$h-\sqrt{3}h=-200$

Factor h from the left side of the equation.

$h(1-\sqrt{3}) =-200$

Divide both sides of the equation by 1 - √3.

$\displaystyle h=\frac{-200}{1-\sqrt{3} }$

Rationalize the denominator by multiplying the numerator and denominator by the conjugate.

$\displaystyle h=\frac{-200}{1-\sqrt{3} } \big{(} \frac{1+\sqrt{3} }{1+\sqrt{3}} \big{)}$
$\displaystyle h=\frac{-200+200\sqrt{3} }{1-3}$
$\displaystyle h =\frac{-200+200\sqrt{3} }{-2}$

Simplify this equation.

$\displaystyle h=100+100\sqrt{3}$
$h=273.20508075$

The height of the lighthouse is about 273 meters.

5 0

3 years ago

Read 2 more answers

(-3,0),(5,-2) find the slope

Mashcka [7]

Answer:

-4

Step-by-step explanation:

Point slope form: y - y = m (x - x)

5 - (-3) = m (-2 - 0)

5 + 3 = m (-2)

8 = m (-2)

m = 8/(-2)

m=4

3 0

3 years ago

I need help on this hhhhhhhh

Anon25 [30]

$\huge\text{Hey there!}$

$\mathsf{\dfrac{10^{15}}{10^4}}$

$\mathsf{10^{15}}\\\mathsf{=10\times10\times10\times10\times10\times10\times10\times10\times10\times10\times 10\times10\times10\times10\times10}\\\mathsf{= \boxed{\bf 1,000,000,000,000,000}}$

$\mathsf{\dfrac{\bold{1,000,000,000,000,000}}{10^4}}$

$\mathsf{10^4}\\\mathsf{= 10\times10\times10\times10}\\\mathsf{10\times10=\bf 100}\\\mathsf{100\times100}\\\mathsf{= \boxed{\bf 10,000}}$

$\mathsf{\dfrac{1,000,000,000,000,000}{\bf 10,000}}$

$\mathsf{\dfrac{1,000,000,000,000,000}{10,000}}\\\\\mathsf{= 1,000,000,000,000,000\div 10,000}\\\\\mathsf{= \boxed{\bf 100,000,000,000}}$

$\mathsf{10^{11}}\\\mathsf{10\times10\times10\times10\times10\times10\times10\times10\times10\times10\times10}\\\mathsf{= \boxed{\bf 100,000,000,000}}$

$\mathsf{100,000,000,000= 100,000,000,000= 10^{11}}$

$\boxed{\boxed{\large\text{Answer: BASICALLY }\mathsf{\dfrac{10^1^5}{10^4}\large\text{ is EQUAL to or EQUIVALENT to}}}}\\\boxed{\boxed{\mathsf{10^{11}}\large\text{ because they both give you the result of \bf 100,000,000,000}}}\huge\checkmark$