Do anyone know this

Make sure is the correct answer please

​

9514 1404 393

  (a)  P = 44 cm + 18 cm + 18 cm = 80 cm

  (b)  396 cm²

  (c)  (i) see attached: radius = 7 cm; height ≈ 16.58 cm; slant height = 18 cm

  (c)  (ii) 7 cm

Step-by-step explanation:

(a) The length of arc PQR is given by the formula ...

  s = rθ . . . . . where r is the radius and θ is the angle in radians

The angle θ in radians is (140°)(π/180°) = (140)(22/7)/(180) = 22/9

So, the arc length is ...

  PQR = (18 cm)(22/9) = 44 cm

Then the perimeter of the figure is ...

  P = PQR +RO +OP = 44 cm + 18 cm + 18 cm

  P = 80 cm

__

(b) The area of a sector is given by ...

  A = 1/2r²θ = 1/2(rs)

  A = (1/2)(18 cm)(44 cm) = 396 cm² . . . area of the sector

__

(c) (i) A drawing of the cone is attached. The "slant height" is 18 cm. The radius is found in part (ii) as 7 cm. The height is given by the Pythagorean theorem:

  height = √((slant height)² - radius²) = √(18² -7²) = √275

  height ≈ 16.58 . . . cm

(ii) The length of arc PQR is the circumference of the base of the cone, given by ...

  C = 2πr . . . . where r is the radius of the base of the cone

Filling in the known values, we find ...

  44 cm = 2(22/7)r

  (44 cm)(7/44) = r = 7 cm . . . . . multiply by 7/44 to find r

The radius of the base of the cone is 7 cm.