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Finding the Fourth Proportional to 57, 78.72 and 51.60

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Solution

The fourth proportional to 57, 78.72 and 51.60 is: 71.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    57 : 78.72 = 51.60 : x
  2. Step 2: Convert to fraction form
    57/78.72 = 51.60/x
  3. Step 3: Cross multiply
    57x = 78.72 × 51.60
  4. Step 4: Simplify right side
    57x = 4,061.95
  5. Step 5: Solve for x
    x = 4,061.95/57
  6. Step 6: Final answer
    x = 71.26

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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.