(i) 60:105::84:147
60 = 60 ÷ 15 = 4 (H.C.F. of 60 and 105 is 15.)
105 105 ÷ 15 7
84 = 84 ÷ 21 = 4 (H.C.F. of 84 and 147 is 21.)
147 147 ÷ 21 7
Hence, 60:105::84:147 are in proportion.
(ii) 91:104::119:136
91 = 91 ÷ 13 = 7 (H.C.F. of 91 and 104 is 13.)
104 104 ÷ 13 8
119 = 119 ÷ 17 = 7 (H.C.F. of 11 and 136 is 17.)
136 136 ÷ 17 8
Hence, 91:104::119:136 are in proportion.
(iii) 108:72::129:86
108 = 108 ÷ 36 = 3 (H.C.F. of 108 and 72 is 36.)
72 72 ÷ 36 2
129 = 129 ÷ 43 = 3 (H.C.F. of 129 and 86 is 43.)
86 86 ÷ 43 2
Hence, 108:72::129:86 are in proportion.
(iv) 39:65::141:235
39 = 39 ÷ 13 = 3 (H.C.F. of 39 and 65 is 13.)
65 65 ÷ 13 5
141 = 141 ÷ 47 = 3 (H.C.F. of 141 and 235 is 47.)
235 235 ÷ 47 5
Hence, 39:65::141:235 are in proportion.