In △ABC\triangle ABC, ADAD is the bisector of ∠A\angle A, meeting side BCBC at DD. If AB=10 cmAB = 10\text{ cm}, AC=14 cmAC = 14\text{ cm}, and BC=6 cmBC = 6\text{ cm}, find the lengths of segments BDBD and DCDC.

Answer: The length of segment BD is 2.5 cm and the length of segment DC is 3.5 cm.

Step-by-step solution

Step 1: Apply the Angle Bisector Theorem

The Angle Bisector Theorem states that if a ray bisects an angle of a triangle, then it divides the opposite side into two segments that are proportional to the other two sides of the triangle. In △ABC\triangle ABC, ADAD bisects ∠A\angle A, so it divides side BCBC into segments BDBD and DCDC such that their ratio is equal to the ratio of the other two sides, ABAB and ACAC.

Step 2: Substitute given values

We are given the lengths of sides AB=10 cmAB = 10\text{ cm} and AC=14 cmAC = 14\text{ cm}. Substitute these values into the proportion derived from the Angle Bisector Theorem.

Step 3: Simplify the ratio and express BD in terms of DC

Simplify the ratio 1014\frac{10}{14} to 57\frac{5}{7}. Then, rearrange the equation to express BDBD in terms of DCDC. This will be useful for solving the system of equations.

Step 4: Use the total length of BC

We know that point DD lies on the side BCBC, so the sum of the lengths of segments BDBD and DCDC must be equal to the total length of BCBC. We are given BC=6 cmBC = 6\text{ cm}.

Step 5: Solve for DC

Substitute the expression for BDBD from step 3 into the equation from step 4. Combine the terms involving DCDC and solve for DCDC.

Step 6: Solve for BD

Now that we have the value of DCDC, we can use the equation BC=BD+DCBC = BD + DC to find the length of BDBD.

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