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Finding the Fourth Proportional to 100.25, 138.29 and 63.40

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Solution

The fourth proportional to 100.25, 138.29 and 63.40 is: 87.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.25 : 138.29 = 63.40 : x
  2. Step 2: Convert to fraction form
    100.25/138.29 = 63.40/x
  3. Step 3: Cross multiply
    100.25x = 138.29 × 63.40
  4. Step 4: Simplify right side
    100.25x = 8,767.59
  5. Step 5: Solve for x
    x = 8,767.59/100.25
  6. Step 6: Final answer
    x = 87.46

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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.