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Finding the Fourth Proportional to 55.30, 76.31 and 30.40

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Solution

The fourth proportional to 55.30, 76.31 and 30.40 is: 41.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.30 : 76.31 = 30.40 : x
  2. Step 2: Convert to fraction form
    55.30/76.31 = 30.40/x
  3. Step 3: Cross multiply
    55.30x = 76.31 × 30.40
  4. Step 4: Simplify right side
    55.30x = 2,319.92
  5. Step 5: Solve for x
    x = 2,319.92/55.30
  6. Step 6: Final answer
    x = 41.95

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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.