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Finding the Fourth Proportional to 100.90, 139.08 and 99.55

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Solution

The fourth proportional to 100.90, 139.08 and 99.55 is: 137.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.90 : 139.08 = 99.55 : x
  2. Step 2: Convert to fraction form
    100.90/139.08 = 99.55/x
  3. Step 3: Cross multiply
    100.90x = 139.08 × 99.55
  4. Step 4: Simplify right side
    100.90x = 13,845.41
  5. Step 5: Solve for x
    x = 13,845.41/100.90
  6. Step 6: Final answer
    x = 137.22

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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.