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3 years ago

If BC = 6 and AD = 5, find DC. 4 4.5 7.2

Mathematics

1 answer:

anygoal [31]3 years ago

4 0

Answer:

The length of CD is 4 units

Step-by-step explanation:

Given the triangle ABC and if BC = 6 units and AD = 5 units

we have to find the length of DC.

In ΔABC and ΔBDC

∠ABC=∠BDC (each 90°)

BC=BC (common)

∠C=∠C (Common)

By ASA rule, ΔABC≈ΔBDC

Therefore their corresponding sides are in proportion

$\frac{BC}{AC}=\frac{BD}{AB}=\frac{CD}{BC}$

$\frac{BC}{AC}=\frac{CD}{BC}$

Let CD=x units

$BC^2=(AC)(CD)$

$6^2=(AD+CD)CD$

$36=(5+x)x$

$36=5x+x^2$

$x^2+5x-36=0$

$x^2+9x-4x-36=0$

$x(x+9)-4(x+9)=0$

$(x-4)(x+9)=0$

x=4, -9

Distance can't be negative therefore

The length of CD is 4 units

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For what values of x is the area of the rectangle greater than the perimeter?

soldier1979 [14.2K]

Area = 7(x + 2) = 7x + 14
Perimeter = 2(7 + x + 2) = 2(9 + x) = 18 + 2x
7x + 14 > 18 + 2x
7x - 2x > 18 - 14
5x > 4
x > 4/5

4 0

3 years ago

10. A perfect circle measuring 38 feet across was discovered on Brickell Avenue in Miami in 1998. Known as the Miami Circle at B

vivado [14]

Using an exponential function, it is found that the Tequesta settlement is 1845 years old.

<h3>What is an exponential function?</h3>

The exponential equation for a decaying amount of a substance is given by:

$A(t) = A(0)e^{-rt}$

In which:

A(0) is the initial value.

r is the decay rate, as a decimal.

Researching on the internet, the half-life of carbon 14 is of 5,730 years, hence A(5730) = 0.5A(0), which we use to find r.

$A(t) = A(0)e^{-rt}$

$0.5A(0) = A(0)e^{-5730r}$

$e^{-5730r} = 0.5$

$\ln{e^{-5730r}} = \ln{0.5}$

$5730r = -\ln{0.5}$

$r = -\frac{\ln{0.5}}{5730}$

$r = 0.00012096809$

Hence, the equation is:

$A(t) = A(0)e^{-0.00012096809t}$

The wood chips were found to contain 80% of the atmospheric carbon-14, hence we have to find t for which A(t) = 0.8A(0).

$A(t) = A(0)e^{-0.00012096809t}$

$0.8A(0) = A(0)e^{-0.00012096809t}$

$e^{-0.00012096809t} = 0.8$

$\ln{e^{-0.00012096809t}} = \ln{0.8}$

$-0.00012096809t = \ln{0.8}$

$t = -\frac{\ln{0.8}}{0.00012096809}$

$t = 1845$

The Tequesta settlement is 1845 years old.

You can learn more about exponential functions at brainly.com/question/25537936

8 0

2 years ago

Show that n(n+1)(n+2) is divisible by 6<br>Solution<br>(

vladimir2022 [97]

Proof by induction

Base case:

n=1: 1*2*3=6 is obviously divisible by six.

Assumption: For every n>1 n(n+1)(n+2) is divisible by 6.

For n+1:

(n+1)(n+2)(n+3)=

(n(n+1)(n+2)+3(n+1)(n+2))

We have assumed that n(n+1)(n+2) is divisble by 6.

We now only need to prove that 3(n+1)(n+2) is divisible by 6.

If 3(n+1)(n+2) is divisible by 6, then (n+1)(n+2) must be divisible by 2.

The "cool" part about this proof.

Since n is a natural number greater than 1 we can say the following:

If n is an odd number, then n+1 is even, then n+1 is divisible by 2 thus (n+1)(n+2) is divisible by 2,so we have proved what we wanted.

If n is an even number" then n+2 is even, then n+1 is divisible by 2 thus (n+1)(n+2) is divisible by 2,so we have proved what we wanted.

Therefore by using the method of mathematical induction we proved that for every natural number n, n(n+1)(n+2) is divisible by 6. QED.

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3 years ago

Max used a base ten blocks to solve the division problem 9.15 divided by 3.

Angelina_Jolie [31]

Answer:

D 3 ones, 0 tenths, 5 hundredths

Step-by-step explanation:

9.15 divided by 3.

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Then, moving the decimal point two units to the left, we have 3.05.

The last number before the decimal point is called ones, which means that we have 3 ones.

The first number after the decimal point is called tenths, which means that we have 0 tenths.

The second number after the decimal point is called hundredths, which means that we have 5 hundredths.

The correct answer is given by option D.

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3 years ago

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zavuch27 [327]

Answer:

Step-by-step explanation: I’m too lazy to do it but just substitute the values into the formula of a Rectangular prism Surface Area

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3 years ago

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