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Finding the Fourth Proportional to 129.10, 178.02 and 90.28

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Solution

The fourth proportional to 129.10, 178.02 and 90.28 is: 124.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.10 : 178.02 = 90.28 : x
  2. Step 2: Convert to fraction form
    129.10/178.02 = 90.28/x
  3. Step 3: Cross multiply
    129.10x = 178.02 × 90.28
  4. Step 4: Simplify right side
    129.10x = 16,071.65
  5. Step 5: Solve for x
    x = 16,071.65/129.10
  6. Step 6: Final answer
    x = 124.49

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.