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Finding the Fourth Proportional to 92.90, 128.16 and 57.92

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Solution

The fourth proportional to 92.90, 128.16 and 57.92 is: 79.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.90 : 128.16 = 57.92 : x
  2. Step 2: Convert to fraction form
    92.90/128.16 = 57.92/x
  3. Step 3: Cross multiply
    92.90x = 128.16 × 57.92
  4. Step 4: Simplify right side
    92.90x = 7,423.03
  5. Step 5: Solve for x
    x = 7,423.03/92.90
  6. Step 6: Final answer
    x = 79.90

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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.