Question

19. A spherical balloon has a circumference of 19cm. what is the approximate surface area of the balloon to the nearest square centimeter?
A) 114 cm^2
B) 460 cm^2
C) 361 cm^2
D) 1,134 cm^2

Answer 1

The main formula of a spherical surface area is SA= 4 x Pi x r²
the circumference is C= 19cm =2 Pi r, so r = C/ 2Pi = 19 / 6.28 =3.02cm
so the surface area can be found by computing
SA= 4x 3.14x 3.02² =114.5, the nearest square centimeter is A) 114 cm^2