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Finding the Fourth Proportional to 56.76, 78.39 and 40.20

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Solution

The fourth proportional to 56.76, 78.39 and 40.20 is: 55.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.76 : 78.39 = 40.20 : x
  2. Step 2: Convert to fraction form
    56.76/78.39 = 40.20/x
  3. Step 3: Cross multiply
    56.76x = 78.39 × 40.20
  4. Step 4: Simplify right side
    56.76x = 3,151.28
  5. Step 5: Solve for x
    x = 3,151.28/56.76
  6. Step 6: Final answer
    x = 55.52

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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.