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Solnce55 [7]
3 years ago
11

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20= A)0 B)210 C)220 D)Brainliest

Mathematics
2 answers:
natulia [17]3 years ago
6 0
The answer is 210 :)
DIA [1.3K]3 years ago
3 0

\\ \rm\longrightarrow 1+2\dots +20

Use Summation formula

\\ \rm\longrightarrow S_n=\dfrac{n(n+1)}{2}

\\ \rm\longrightarrow S_{20}=\dfrac{20(20+1)}{2}

\\ \rm\longrightarrow S_{20}=\dfrac{20(21)}{2}

\\ \rm\longrightarrow S_{20}=\dfrac{420}{2}

\\ \rm\longrightarrow S_{20}=210

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nikdorinn [45]
It's a horizontal line
4 0
3 years ago
Eva maintained an average speed of 35 miles per hour (mph) for the first m hours of her road trip. For the next n hours of the t
Schach [20]

Answer:

Step-by-step explanation:

I don't see the choices, but I will make the equations that seems to be correct to me.

Known facts:

  • maintained an average speed of 35 miles per hour (mph) for the first m hours of her road trip.
  • next n hours of the trip, she drove at an average speed of 60 mph.
  • Eva drove a total of 225 miles in 4.5 hours.

Let's make the equations:

m + n = 4.5

35m + 60n = 225

Hope that helps!

7 0
3 years ago
Proof that :<br><img src="https://tex.z-dn.net/?f=%20%7Bsin%7D%5E%7B2%7D%20%5Ctheta%20%2B%20%20%7Bcos%7D%5E%7B2%7D%20%5C%3A%5Cth
Arisa [49]

Answer:

Solution given:

Right angled triangle ABC is drawn where <C=\theta

we know that

\displaystyle Sin\theta=\frac{opposite}{hypotenuse} =\frac{AB}{AC}

\displaystyle Cos\theta=\frac{adjacent}{hypotenuse}=\frac{BC}{AC}

Now

left hand side

\displaystyle {sin}^{2} \theta + {cos}^{2} \:\theta

Substituting value

(\frac{AB}{AC})²+(\frac{BC}{AC})²

distributing power

\frac{AB²}{AC²}+\frac{BC²}{AC²}

Taking L.C.M

\displaystyle \frac{AB²+BC²}{AC²}....[I]

In ∆ABC By using Pythagoras law we get

\boxed{\green{\bold{Opposite²+adjacent²=hypotenuse²}}}

AB²+BC²=AC²

Substituting value of AB²+BC² in equation [I]

we get

\displaystyle \frac{AC²}{AC²}

=1

Right hand side

<h3><u>proved</u></h3>

8 0
3 years ago
Read 2 more answers
Can someone explain how to do this? Will mark as brainliest
masya89 [10]

Answer: x is the angle of the tricundicular angle of the imperfect triangle. It’s like area but it’s an imperfect triangle, there’s is also 2 different numbers that u should get from this

Step-by-step explanation: pls mark brainliest

4 0
3 years ago
Give the starting value a, the growth factor b, and the growth rate r if Q = abt = a(1 + r)t . Write r as a percent.
Misha Larkins [42]

Answer:

Option a:

a=79

b=1.002

r=0.2%

Step-by-step explanation:

Q = 79 (1.002)^t

Q = a b^t = a (1+r)^t

Comparing with the formulas:

a=79

b=1.002

1+r=1.002

Solving for r: Subtrating 1 both sides of the equation:

1+r-1 = 1.002 - 1

r = 0.002

Writting r as percent:

r = (0.002) 100%

r = 0.2%

3 0
4 years ago
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