Question

OAB is a sector of a circle of radius 12cm having centre O. Find a difference between area ofsector OAB and sector AOB.angle AOB is45 degree​

Answer 1

Answer:

Area of sector OAB =

α/360*πr²

=45/360*22/7*12*12

=56.52cm²

And are of sector aob=

α/360*πr²

=315/360*22/7*12*12

=395.64cm²

Now difference of sector AOB and OAB =

395.64-56.52=339.62cm²

Answer 2

AnswEr:-

Given the radius of the circle r = 12 cm

Angle subtended by the arc AB at the centre θ = 45°

Area of sector with radius r and angle in degrees θ, is given by

⇒ θ / 360°  ×πr²

Area of the circle    =  πr²

Area of the sector OAB =  45/360  × πr²

                                      =  1/8 × πr²

Area of sector AOB can be calculated as Area of the Circle -  Area of sector OAB

∴ Area of sector AOB  =  πr² - 1/8 (πr²)

                  = πr²(7/8)

Difference between area of sector AOB and OAB ,

   = 7/8 πr² - 1/8 πr²

     = 3/4 πr²

= 3/4 ×  22/7 ×12 × 12

=339.43 cm².

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