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Finding the Fourth Proportional to 100.96, 139.15 and 77.60

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Solution

The fourth proportional to 100.96, 139.15 and 77.60 is: 106.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.96 : 139.15 = 77.60 : x
  2. Step 2: Convert to fraction form
    100.96/139.15 = 77.60/x
  3. Step 3: Cross multiply
    100.96x = 139.15 × 77.60
  4. Step 4: Simplify right side
    100.96x = 10,798.19
  5. Step 5: Solve for x
    x = 10,798.19/100.96
  6. Step 6: Final answer
    x = 106.96

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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.