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Finding the Fourth Proportional to 57.15, 78.84 and 55.38

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Solution

The fourth proportional to 57.15, 78.84 and 55.38 is: 76.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    57.15 : 78.84 = 55.38 : x
  2. Step 2: Convert to fraction form
    57.15/78.84 = 55.38/x
  3. Step 3: Cross multiply
    57.15x = 78.84 × 55.38
  4. Step 4: Simplify right side
    57.15x = 4,366.16
  5. Step 5: Solve for x
    x = 4,366.16/57.15
  6. Step 6: Final answer
    x = 76.40

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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.