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3 years ago

Find the perimeter of an isosceles triangle whose base is 40 cm and whose base angle is 70".

Mathematics

2 answers:

ivanzaharov [21]3 years ago

7 0

$cos70^o=\frac{20}{x}\\\\cos70^o\approx0.342\\\\\frac{20}{x}=0.342\\\\0.342x=20\ \ \ \ /:0.342\\\\x\approx58.5\ (cm)\\\\Perimeter:40cm+2\cdot58.5cm=157cm$

liq [111]3 years ago

3 0

$cos70^0= \frac{20}{x}\\\\x= \frac{20}{cos70^0} \\\\the\ perimeter\ is:\\\\ P=2x+40=\frac{40}{cos70^0}+40 \ \ \ and\ \ \ cos70^0\approx0.3420\\\\P\approx\frac{40}{0.342}+40\approx156.96\ [cm]$

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Answer:

<em>Alex sold 330 white chocolate bars</em>

Step-by-step explanation:

let the milk chocolate candy be x and the white chocolate candy be y. then

then 2x+3y=990----1)

x+y=330-----2)

from eq 2) ⇒ x=330-y---------3)

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3 years ago

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Vikentia [17]

Answer:

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Step-by-step explanation:

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2 years ago

Use the graph below to estimate the solution to the system of equations shown.

Mila [183]

Answer: The second choice is answer.

Step-by-step explanation:

<h3>The first line (Blue One)</h3>

$y=-x-3$ (Slope is -1 and intercepts y at -3)

<h3>The second one (Red One)</h3>

$y=2x-8$ (Slope is 2, to find y-intercept. Substitute x = 0 then we get -8) (For x-intercept, it's 4. Just substitute y=0 to get x-intercept.)

Because there are choices, it's easy to notice.

The first one, x = -4 and almost -5 which is not right. (x is around 1 almost 2.)

The second one, x = 1 and almost 2 is right.

The third one, x = -1 and almost -2 is not right (The intersection isn't even at -1 or any negative number for x-axis.)

The fourth one, just like the first one... x = 4 almost 5

<h3>Or solve the equations.</h3>

$y=-x-3\\y=2x-8$

Substitute y=2x-8 in y=-x-3

$2x-8=-x-3\\2x-8+x+3=0\\3x-5=0\\3x=5\\x=\frac{5}{3}\\(x=1\frac{2}{3})$

Look at the value of x then find the answer that matches the value of x.

Now for y, substitute x = 5/3 in y = -x-3 (or in 2x-8 if you want.)

$y=-\frac{5}{3} -3\\y=-\frac{5}{3} -\frac{9}{3} \\y=-\frac{14}{3} \\(y=-4\frac{2}{3} )$

So the answer is the second choice.

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4 years ago