Jika luas bangun tersebut 462 cm², kelilingnya adalah...

Kelas 8 Matematika
Bab Lingkaran

luas 3/4 lingkaran = 462
3/4 . π . r . r = 462
3/4 . 22/7 . r² = 462
r² = 462 . 28/66
r = √(196)
r = 14 cm

Keliling
= (3/4 . 2 . π . r) + 2r
= (3/2 . 22/7 . 14) + 2 . 14
= 66 + 28
= 94 cm

L 3/4 lingkaran = 3/4. π.r^2
462 = 3/4 . 22/7 .r^2
462 = 33/14.r^2
462 : 33/14 = r^2
196 = r^2
√196 = r
14 = r

K 3/4 lingkaran = 3/4. π.d + 2r
= 3/4.22/7.28 + 2.14
= 66+28
= 94