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Finding the Fourth Proportional to 178.40, 246.20 and 100.78

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Solution

The fourth proportional to 178.40, 246.20 and 100.78 is: 139.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    178.40 : 246.20 = 100.78 : x
  2. Step 2: Convert to fraction form
    178.40/246.20 = 100.78/x
  3. Step 3: Cross multiply
    178.40x = 246.20 × 100.78
  4. Step 4: Simplify right side
    178.40x = 24,812.04
  5. Step 5: Solve for x
    x = 24,812.04/178.40
  6. Step 6: Final answer
    x = 139.08

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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.