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Finding the Fourth Proportional to 56.30, 77.60 and 39.90

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Solution

The fourth proportional to 56.30, 77.60 and 39.90 is: 54.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    56.30 : 77.60 = 39.90 : x
  2. Step 2: Convert to fraction form
    56.30/77.60 = 39.90/x
  3. Step 3: Cross multiply
    56.30x = 77.60 × 39.90
  4. Step 4: Simplify right side
    56.30x = 3,096.34
  5. Step 5: Solve for x
    x = 3,096.34/56.30
  6. Step 6: Final answer
    x = 54.99

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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.