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Finding the Fourth Proportional to 172.07, 257.99 and 85.30

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Solution

The fourth proportional to 172.07, 257.99 and 85.30 is: 127.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.07 : 257.99 = 85.30 : x
  2. Step 2: Convert to fraction form
    172.07/257.99 = 85.30/x
  3. Step 3: Cross multiply
    172.07x = 257.99 × 85.30
  4. Step 4: Simplify right side
    172.07x = 22,005.48
  5. Step 5: Solve for x
    x = 22,005.48/172.07
  6. Step 6: Final answer
    x = 127.89

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.