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Finding the Fourth Proportional to 291.90, 438.04 and 129.72

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Solution

The fourth proportional to 291.90, 438.04 and 129.72 is: 194.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.90 : 438.04 = 129.72 : x
  2. Step 2: Convert to fraction form
    291.90/438.04 = 129.72/x
  3. Step 3: Cross multiply
    291.90x = 438.04 × 129.72
  4. Step 4: Simplify right side
    291.90x = 56,822.55
  5. Step 5: Solve for x
    x = 56,822.55/291.90
  6. Step 6: Final answer
    x = 194.66

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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.