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3 years ago

Find the area of a regular decagon with radius 4 cm

2 answers:

8 0

$A = \frac{5}{2}t^{2} \sqrt{5 + 2 \sqrt{5} }$

$A = \frac{5}{2} (4)^{2} \sqrt{5 + 2(2.236067978)} }$

$A = \frac{5}{2} (16) \sqrt{5 + 4.472135956}$

$A = 40 \sqrt{9.472135956}$

$A = 40(3.077683537)$

$A = 123.1073415cm^{2}$

emmasim [6.3K]3 years ago

5 0

The area is 123.1073415 cm

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What is the surface area of this square pyramid? <br> HELP!

aniked [119]

Answer:

A≈149.84

Step-by-step explanation:

A=a2+2aa2

4+h2=62+2·6·62

4+92≈149.842

3 0

3 years ago

An insured's roof cost $4,000 when installed 5 years ago. It has been damaged by hail and must be replaced. The new roof will co

hoa [83]

Answer:

ACV=$4,500

Step-by-step explanation:

We have that the actual cash value (ACV) is defined as:

$ACV=\dfrac{R\times(E-C)}{E}$

Where:

$ACV =$ actual cash value

$R =$ replacement cost or purchase price of the item

$E =$ expected life of the item

$C =$ current life of the item

Then we have R=$6,000, C=5years, and to find the expected life of the item we can use the depreciating of the roof, then if the roof is depreciating $200 each year we just need to divide $4,000 by $200 to find the expected life of the roof:

$\dfrac{4,000}{200}=20$

Then the espected life of the roof is 20 years, with this result we have all the data, then:

$ACV=\dfrac{\$6,000\times (20-5)}{20}=\dfrac{\$6,000\times (15)}{20}=\dfrac{\$90,000}{20}=\$4,500$

Then the ACV is $4,500

5 0

3 years ago

Find the length of CD

laiz [17]

Answer:

Step-by-step explanation:

Calculate the length using the distance formula

d = √ (x₂ - x₁ )² + (y₂ - y₁ )²

with (x₁, y₁ ) = C(3, - 2) and (x₂, y₂ ) = D(7, - 8)

CD = $\sqrt{(7-3)^2+(-8+2)^2}$

= $\sqrt{4^2+(-6)^2}$

= $\sqrt{16+36}$

= $\sqrt{52}$ ≈ 7.2 → D

5 0

3 years ago

Read 2 more answers

Consider the statement : Congruent triangles are always similar. Which of the following statements is an example of the statemen

swat32

Answer:

Yes, the congruent triangles are always similar. The following statements are applicable

1) Angles are the same, but sides are proportional to eachother.

2) Sides are the same size.

3)Corresponding angles and corresponding sides are congruent.

Step-by-step explanation:

Yes, they are similar.

For two triangles to be similar, it is sufficient if two angles of one triangle are equal to two angles of the other triangle. Note that if two angles of one are equal to two angles of the other triangle, the third angles of the two triangles too will be equal.

If two triangles are congruent then all corresponding sides as well as corresponding angles of one triangle are equal to those of other triangles. This can happen in four cases

1)- when all sides of triangles are equal,

2) - if one side and two angles of one are equal to one side and two angles of other triangle.

3) - if two sides and included angle of one triangle are equal to two sides and included angle of other triangle

4)- if in two right angled triangles, one side and hypotenuse of one triangle are equal to one side and hypotenuse of other triangle.

Observe that for triangles to be similar, we just need all angles to be equal. But for triangles to be congruent, angles as well as sides should be equal.

Hence, while congruent triangles are similar, similar triangles may not be congruent ( but the converse is not true) .

4 0

3 years ago

Solve the equation.

nadya68 [22]

Answer:

A. No solution

Step-by-step explanation:

The given equation is 4(2 x + 9) = 4(2 x +6)

We divide through by 4 to get:

2 x + 9 = 2 x +6

We now group similar terms to obtain:

$2x - 2x = 6 - 9$

$0 = - 3$

This final statement is false.

Therefore the given equation has no solution.

7 0

3 years ago