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Finding the Fourth Proportional to 56.74, 78.16 and 42.90

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Solution

The fourth proportional to 56.74, 78.16 and 42.90 is: 59.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.74 : 78.16 = 42.90 : x
  2. Step 2: Convert to fraction form
    56.74/78.16 = 42.90/x
  3. Step 3: Cross multiply
    56.74x = 78.16 × 42.90
  4. Step 4: Simplify right side
    56.74x = 3,353.37
  5. Step 5: Solve for x
    x = 3,353.37/56.74
  6. Step 6: Final answer
    x = 59.10

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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.