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Finding the Fourth Proportional to 56.40, 78.24 and 55.68

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Solution

The fourth proportional to 56.40, 78.24 and 55.68 is: 77.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.40 : 78.24 = 55.68 : x
  2. Step 2: Convert to fraction form
    56.40/78.24 = 55.68/x
  3. Step 3: Cross multiply
    56.40x = 78.24 × 55.68
  4. Step 4: Simplify right side
    56.40x = 4,356.40
  5. Step 5: Solve for x
    x = 4,356.40/56.40
  6. Step 6: Final answer
    x = 77.24

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.