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Finding the Fourth Proportional to 102.80, 139.05 and 102.80

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Solution

The fourth proportional to 102.80, 139.05 and 102.80 is: 139.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.80 : 139.05 = 102.80 : x
  2. Step 2: Convert to fraction form
    102.80/139.05 = 102.80/x
  3. Step 3: Cross multiply
    102.80x = 139.05 × 102.80
  4. Step 4: Simplify right side
    102.80x = 14,294.34
  5. Step 5: Solve for x
    x = 14,294.34/102.80
  6. Step 6: Final answer
    x = 139.05

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Why These Related Problems?

These problems maintain the same ratio (1.35) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.