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The perimeters of two similar triangles ...

The perimeters of two similar triangles `triangle ABC` and `triangle PQR` are 36 cm and 24 cm respectively. IfPQ = 10 cm, the AB is

A

15 cm

B

12 cm

C

14 cm

D

26 cm

Text Solution

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The correct Answer is:
To find the length of side AB in triangle ABC given the perimeters of two similar triangles and the length of side PQ in triangle PQR, we can follow these steps: ### Step-by-Step Solution: 1. **Understand the relationship between similar triangles**: Since triangles ABC and PQR are similar, the ratio of their corresponding sides is equal to the ratio of their perimeters. 2. **Write down the given information**: - Perimeter of triangle ABC = 36 cm - Perimeter of triangle PQR = 24 cm - Length of side PQ = 10 cm 3. **Set up the ratio of the perimeters**: \[ \frac{\text{Perimeter of } ABC}{\text{Perimeter of } PQR} = \frac{36}{24} \] 4. **Simplify the ratio**: \[ \frac{36}{24} = \frac{3}{2} \] This means the ratio of the sides of triangle ABC to triangle PQR is also \( \frac{3}{2} \). 5. **Set up the equation for the corresponding sides**: Let AB be the corresponding side to PQ. Then: \[ \frac{AB}{PQ} = \frac{3}{2} \] Substituting the value of PQ: \[ \frac{AB}{10} = \frac{3}{2} \] 6. **Cross-multiply to solve for AB**: \[ AB \cdot 2 = 10 \cdot 3 \] \[ 2AB = 30 \] 7. **Divide both sides by 2**: \[ AB = \frac{30}{2} = 15 \text{ cm} \] ### Final Answer: The length of side AB is **15 cm**. ---
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