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Find the area of the following circles, given that: $(Take\ \pi=\frac{22}{7})$
$(a)$ radius = 14 mm
$(b)$ diameter = 49 m
$(c)$ radius = 5 cm

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Tutorialspoint

Updated on 10-Oct-2022 13:36:00

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$(a)$. Here, $r=14\ mm$Area of the circle$=\pi r^2$$=\pi\times14\times14$$=\frac{22}{7}\times14\times14$$=616\ mm^2$$(b)$. Here, diameter$=49\ m$$r=\frac{49}{2}\ m$Area$=\pi r^2$$=\frac{22}{7}\times\frac{49}{2}\times\frac{49}{2}$ $=\frac{3773}{2}\ m^2$$=1886.5\ m^2$ $(c)$. Here, radius$=5\ cm$Area$=\pi r^2$$=\frac{22}{7}\times5\times5$$=\frac{550}{7}\ m^2$$=78.57\ cm^2$

If the circumference of a circular sheet is $154\ m$, find its radius. Also find the area of the sheet. $(Take\ \pi=\frac{22}{7})$

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Tutorialspoint

Updated on 10-Oct-2022 13:36:00

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Given:The circumference of a circular sheet is \( 154 \mathrm{~m} \).To do:We have to find the radius and area of the sheet.Solution:Let the radius of the sheet be $r$.This implies, $2 \pi r=154\ m$$2\times\frac{22}{7}\times r=154$$r=\frac{7\times7}{2}$$r=\frac{49}{2}\ m$Area of the sheet$= \pi r^2$$=\frac{22}{7}\times\frac{49}{2}\times\frac{49}{2}$$=\frac{11\times7\times49}{2}$$=\frac{3773}{2}$$=1886.5\ m^2$The radius of the sheet is $24.5\ m$ and ... Read More

A gardener wants to fence a circular garden of diameter $21\ m$. Find the length of the rope he needs to purchase, if he makes 2 rounds of fence. Also find the cost of the rope, if it costs $₹\ 4$ per meter. $(Take\ \pi=\frac{22}{7})$

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Tutorialspoint

Updated on 10-Oct-2022 13:36:00

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Diameter of the circular garden$=21\ m$Radius$=\frac{21}{2}\ m$ Circumference$=2\pi r$$=2\times\frac{22}{7}\times\frac{21}{2}$​$=66\ m$Length of rope needed for 2 rounds$=2\times66\ m=132\ m$Cost of the rope$=Rs\ 4\times132=Rs\ 528$

From a circular sheet of radius $4\ cm$, a circle of radius $3\ cm$ is removed. Find the area of the remaining sheet. $(Take\ \pi=3.14)$

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Tutorialspoint

Updated on 10-Oct-2022 13:36:00

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Given:Radius of circular sheet$=4\ cm$.Radius of the circle removed$=3\ cm$.To do:We have to find the area of the remaining sheet.Solution:The area of the circular sheet with $4\ cm$ radius $=\pi (4)^2=16 \pi$The area of the circular sheet with $3\ cm$ radius $=\pi (3)^2=9 \pi$Area of the remaining sheet$=$Area of the ... Read More

Saima wants to put a lace on the edge of a circular table cover of diameter 1.5 m. Find the length of the lace required and also find its cost if one meter of the lace costs ₹ 15. $(Take\ \pi=3.14)$

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Tutorialspoint

Updated on 10-Oct-2022 13:36:00

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From the question it is given that, Diameter of the circular table $= 1.5\ m$We know that, radius $(r)=\frac{d}{2}$$=\frac{1.5}{2}$$=0.75\ m$Then, the Circumference of the circle$=2\pi r$$=2\times 3.14\times 0.75$$=4.71\ m$So, the length of lace$=4.71\ m$Cost of $1\ m$ lace$=Rs.\ 15$     [given]Cost of $4.71\ m$ lace $=Rs.\ 15\times 4.71$$=Rs.\ 70.65$Read More

Find the perimeter of the adjoining figure, which is a semicircle including its diameter.
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Tutorialspoint

Updated on 10-Oct-2022 13:36:00

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Diameter$=10\ cm$$r=\frac{10}{2}\ cm$$=5\ cm$The perimeter of a semicircle$=\pi r$$=\frac{110}{7}cm+diameter$$=\frac{110}{7}\ cm+10\ cm$ $=(\frac{110+70}{7})\ cm$$=\frac{180}{7}\ cm$$=25.71\ cm$ Hence the required perometer$=25.7\ cm\ (approx.)$

∆ABC is right angled at $A$ $(Fig\ 11.25)$. $AD$ is perpendicular to $BC$. If $AB = 5\ cm,\ BC = 13\ cm$ and $AC = 12\ cm$, Find the area of $∆ABC$. Also find the length of $AD$.
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Tutorialspoint

Updated on 10-Oct-2022 13:35:58

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Given: ∆ABC is right angled at $A$ $(Fig\ 11.25)$. $AD$ is perpendicular to $BC$. If $AB = 5\ cm, \ BC = 13\ cm$ and $AC = 12\ cm$.To do: To find the area of $∆ABC$ and also find the length of $AD$.Solution:Area of right triangle $ABC=\frac{1}{2}\times AB\times AC$$=\frac{1}{2}\times5\times12$$=30\ cm^2$ Area of $\triangle ... Read More

Find the area of each of the following parallelograms:
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Tutorialspoint

Updated on 10-Oct-2022 13:35:55

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To do: To find the area of each of the given parallelograms.Solution:$(a)$. Area of the parallelogram$=base\times altitude$$=7\ cm\times4\ cm$$=28\ cm^2$$(b)$. Area of the parallelogram$=base\times altitude$$=5\ cm\times3\ cm$$=15\ cm^2$$(c)$. Area of the parallelogram$=base\times altitude$$=2.5\ cm\times3.5\ cm$ $=8.75\ cm^2$$(d)$. Area of the parallelogram$=base\times altitude$$=5\ cm\times4.8\ cm$$=24\ cm^2$ $(e)$. Area of the parallelogram$=base\times altitude$$=2\ cm\times4.4\ cm$$=8.8\ ... Read More

Find the missing values:
BaseHeightArea of Triangle
$15\ cm$
$87\ cm^2$
$31.4\ mm$$1256\ mm^2$
$22\ cm$$170.5\ cm^2$
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Tutorialspoint

Updated on 10-Oct-2022 13:35:54

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$(a)$. Area of the triangle $= 87\ cm^2$Base $= 15\ cm$Area of a triangle $= \frac{1}{2}\times Base\times Height$$87\ cm^2 = \frac{1}{2}\times 15\ cm\times Height$Height $= \frac{87\ cm^2\times 2}{15\ cm}$Height $= \frac{174\ cm^2}{15\ cm}$Height $= 11.6\ cm$$(b)$. Area of the triangle $= 1256\ mm^2$Height $= 31.4\ mm$Area of triangle $= \frac{1}{2}\times ... Read More

Find the area of each of the following triangles:
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Tutorialspoint

Updated on 10-Oct-2022 13:35:54

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To do: To find the are of each of the given triangles.Solution: $(a)$. Area of the triangle$=\frac{1}{2}\times b\times h$ $=\frac{1}{2}\times4\ cm\times3\ cm$ $=6\ cm^2$$(b)$. Area of the triangle$=\frac{1}{2}\times b\times h$$\frac{1}{2}\times5\ cm\times3.2\ cm$$=8.0\ cm^2$$(c)$. Area of the triangle$=\frac{1}{2}\times b\times h$$=\frac{1}{2}\times3\ cm\times4\ cm$$=6\ cm^2$$(d)$ Area of the triangle$=\frac{1}{2}\times b\times h$$=\frac{1}{2}\times3\ cm\times2\ cm$$=3\ cm^2$Read More

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