c). luas dan keliling ABCD

Luas juring BOC= 72/360 × 22/7 × 14 × 14 = 123,2 cm^2
Luas juring AOD= 72/360 × 22/7 × 7 × 7 = 30,8 cm^2
Luas ABCD= luas juring BOC-luas juring AOD= 123,2-30,8= 92,4 cm^2
Keliling ABCD= (72/360 × 2 × 22/7 × 7) + (72/360 × 2 × 22/7 × 14) + 7 + 7 = 8,8+17,6+14= 40,4 cm