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Finding the Fourth Proportional to 56.80, 78.48 and 42.28

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Solution

The fourth proportional to 56.80, 78.48 and 42.28 is: 58.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.80 : 78.48 = 42.28 : x
  2. Step 2: Convert to fraction form
    56.80/78.48 = 42.28/x
  3. Step 3: Cross multiply
    56.80x = 78.48 × 42.28
  4. Step 4: Simplify right side
    56.80x = 3,318.13
  5. Step 5: Solve for x
    x = 3,318.13/56.80
  6. Step 6: Final answer
    x = 58.42

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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.