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Finding the Fourth Proportional to 99.90, 137.87 and 63.05

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Solution

The fourth proportional to 99.90, 137.87 and 63.05 is: 87.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    99.90 : 137.87 = 63.05 : x
  2. Step 2: Convert to fraction form
    99.90/137.87 = 63.05/x
  3. Step 3: Cross multiply
    99.90x = 137.87 × 63.05
  4. Step 4: Simplify right side
    99.90x = 8,691.94
  5. Step 5: Solve for x
    x = 8,691.94/99.90
  6. Step 6: Final answer
    x = 87.01

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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.