keliling tembereng pada gambar di bawah berikut adalah!!!

Gunakan 2\pi r = \pi d.
Panjang SP
= 72/360 x 22/7 x 14
= 1/5 x 44
= 44/5
Panjang RQ
= 72/360 x 22/7 x 28
= 1/5 x 88
= 88/5
Keliling yang diarsir,
= SP + PQ + QR + SR
= 44/5 + 7 + 88/5 + 7
= 132/5 + 14
= 26,4 + 14
= 40,4 cm

Keliling daerah yang diarsir :

panjang busur QR = 72/360 x 2.phi.14
                               = 1/5 x 2 x 22/7 x 14
                               = 17,6 cm

panjang busur PS = 72/360 x 2.phi.7
                              = 1/5 x 2 x 22/7 x 7
                              = 8,8 cm

keliling PQRS = PQ + QR + RS + PS
                       = 7 + 17,6 + 7 + 8,8
                       = 40,4 cm