1. **State the problem:** We have points A, B, C, and D on a straight line with AC = 98 cm and AB = 35 cm. We need to find BC and then find AD given BC is 3 times CD. 2. **Find BC:** Since points are on a line, AC = AB + BC. $$ BC = AC - AB = 98 - 35 = 63 \text{ cm} $$ 3. **Express BC and CD relationship:** Given BC is 3 times CD, let CD = x. Then, $$ BC = 3x $$ From step 2, $$ 63 = 3x \Rightarrow x = \frac{63}{3} = 21 \text{ cm} $$ So, $$ CD = 21 \text{ cm} $$ 4. **Find AD:** Since points are on a line in order A, B, C, D, $$ AD = AB + BC + CD = 35 + 63 + 21 = 119 \text{ cm} $$ **Final answers:** - Length of BC is $63$ cm. - Length of AD is $119$ cm.