Practicing Success
In triangle ABC, AD is the bisector of ∠A. If AB = 5 cm, AC = 7.5 cm and BC = 10 cm, then what is the distance of D from the mid-point of BC (in cm) ? |
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AD is the bisector of \(\angle\)A = \(\frac{AB}{AC}\) = \(\frac{BD}{DC}\) [By angle bisector theorem] = \(\frac{5}{7.5}\) = \(\frac{BD}{DC}\) = \(\frac{2}{3}\) = \(\frac{BD}{DC}\) = \(\frac{3}{2}\) = \(\frac{DC}{BD}\) Adding 1 to both sides, we get = \(\frac{3}{2}\) + 1 = \(\frac{DC}{BD}\) + 1 = \(\frac{5}{2}\) = \(\frac{BD\;+\;DC}{BD}\)= \(\frac{BC}{BD}\) Since BC = 10, we get The value of BD = (\(\frac{2}{5}\) x 10) = 4 The value of DC = (\(\frac{3}{5}\) x 10) = 6 ACT Midpoint of BC = \(\frac{10}{2}\) = 5 So, we take M as midpoint on BC = 5 Now, The distance between D and M = (6 - 5) = 1 Therefore, answer 1 cm. |