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Finding the Fourth Proportional to 100.90, 139 and 73.08

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Solution

The fourth proportional to 100.90, 139 and 73.08 is: 100.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.90 : 139 = 73.08 : x
  2. Step 2: Convert to fraction form
    100.90/139 = 73.08/x
  3. Step 3: Cross multiply
    100.90x = 139 × 73.08
  4. Step 4: Simplify right side
    100.90x = 10,158.12
  5. Step 5: Solve for x
    x = 10,158.12/100.90
  6. Step 6: Final answer
    x = 100.68

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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.