3 years ago

The perimeter of the semicircle is 25.71 cm. Calculate the value of radius x. Take pi to be 3.142

Mathematics

1 answer:

yan [13]3 years ago

5 0

Answer:

5 cm

Step-by-step explanation:

$Perimeter of semicircle = \frac{1}{2} \times 2\pi \: x +2x\\ 25.71 = 3.14 2\times x+ 2x\\ 25.71 = 5.14 2 x\\ x = \frac{25.71}{5.142} \\ x = 5 \: cm$

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Solve the following system of equations by using the provided grid: y= -x + 3, y = 3/2x - 2

GenaCL600 [577]

Y = -x + 3
y = 3/2x - 2

-x + 3 = 3/2x - 2....multiply everything by 2 to get rid of the fraction
-2x + 6 = 3x - 4
-2x - 3x = -4 - 6
-5x = -10
x = -10/-5
x = 2

y = -x + 3
y = -2 + 3
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solution is (2,1)

4 0

3 years ago

An exterior angle of a regular convex polygon is 40°. What is the number of sides of the polygon?

seraphim [82]

Answer:

option B

Step-by-step explanation:

Sum of interior angles of a polygon with n sides:

$= (n - 2 )\times 180$

$Therefore, Each \ interior \ angle = (\frac{n - 2}{n} )\times 180$

$Sum \ of \ one \ of \ the \ interior \ angle \ with \ its \ exterior \ angle \ is \ 180^\circ$

$[ \ because \ straight \ line \ angle = 180^\circ \ ]$

That is ,

$Exterior \ angle + Interior \ angle = 180^\circ\\\\40^ \circ + (\frac{n-2}{n}) \times 180 = 180^\circ\\\\40 n + 180n - 360 = 180n\\\\40n = 180n - 180n + 360 \\\\40n = 360 \\\\n = 9$