Question

An arc of length 15.7 cm subtends a right angle at the centre of the circle find the radius

Answer 1

Answer:

r = 10 cm

Step-by-step explanation:

Given that ,the length of arc (l) of the circle whose subtends a right angle at centre of the circle = 15.7cm

To find the radius of the circle (r) .

As per given data ,

l = 15.7 cm

∅ = π/2

r = ?

By using the formula,

∅ = l/r

π/2 = 15.7/r

r =  ( 15.7×7×2) / 22

r = ( 15.7×7) / 11

r = ( 109.9) / 11

r =9.999

r = 10 cm

Therefore the radius of circle is 10 cm .

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Answer 2

Answer:

The radius of circle is 10cm having an arc of length 15.7cm.

Step-by-step explanation:

Given that the length of the arc =15.7cm

We know the relation:

The length of an arc $= (\frac{\theta}{360})*2\pi r$        .........(1)

where r =radius and $\pi =3.14, \theta =90^{o}$

Put these values in eq.(1)

   ∴       $15.7=(\frac{90}{360})*(2)(3.14)(r)\\ \\ r=\frac{15.7}{1.57 }\\ \\ r=10cm$