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Finding the Fourth Proportional to 172.40, 257.12 and 155.12

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Solution

The fourth proportional to 172.40, 257.12 and 155.12 is: 231.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.40 : 257.12 = 155.12 : x
  2. Step 2: Convert to fraction form
    172.40/257.12 = 155.12/x
  3. Step 3: Cross multiply
    172.40x = 257.12 × 155.12
  4. Step 4: Simplify right side
    172.40x = 39,884.45
  5. Step 5: Solve for x
    x = 39,884.45/172.40
  6. Step 6: Final answer
    x = 231.35

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.