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Finding the Fourth Proportional to 56.74, 78.21 and 42.88

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Solution

The fourth proportional to 56.74, 78.21 and 42.88 is: 59.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.74 : 78.21 = 42.88 : x
  2. Step 2: Convert to fraction form
    56.74/78.21 = 42.88/x
  3. Step 3: Cross multiply
    56.74x = 78.21 × 42.88
  4. Step 4: Simplify right side
    56.74x = 3,353.64
  5. Step 5: Solve for x
    x = 3,353.64/56.74
  6. Step 6: Final answer
    x = 59.11

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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.