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Finding the Fourth Proportional to 130.50, 180.09 and 78.78

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Solution

The fourth proportional to 130.50, 180.09 and 78.78 is: 108.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.50 : 180.09 = 78.78 : x
  2. Step 2: Convert to fraction form
    130.50/180.09 = 78.78/x
  3. Step 3: Cross multiply
    130.50x = 180.09 × 78.78
  4. Step 4: Simplify right side
    130.50x = 14,187.49
  5. Step 5: Solve for x
    x = 14,187.49/130.50
  6. Step 6: Final answer
    x = 108.72

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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.