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Finding the Fourth Proportional to 63.90, 88.13 and 61.40

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Solution

The fourth proportional to 63.90, 88.13 and 61.40 is: 84.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    63.90 : 88.13 = 61.40 : x
  2. Step 2: Convert to fraction form
    63.90/88.13 = 61.40/x
  3. Step 3: Cross multiply
    63.90x = 88.13 × 61.40
  4. Step 4: Simplify right side
    63.90x = 5,411.21
  5. Step 5: Solve for x
    x = 5,411.21/63.90
  6. Step 6: Final answer
    x = 84.68

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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.