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Finding the Fourth Proportional to 130.78, 180.43 and 99.66

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Solution

The fourth proportional to 130.78, 180.43 and 99.66 is: 137.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.78 : 180.43 = 99.66 : x
  2. Step 2: Convert to fraction form
    130.78/180.43 = 99.66/x
  3. Step 3: Cross multiply
    130.78x = 180.43 × 99.66
  4. Step 4: Simplify right side
    130.78x = 17,982.08
  5. Step 5: Solve for x
    x = 17,982.08/130.78
  6. Step 6: Final answer
    x = 137.50

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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.