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Finding the Fourth Proportional to 130.87, 180.58 and 99.78

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Solution

The fourth proportional to 130.87, 180.58 and 99.78 is: 137.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.87 : 180.58 = 99.78 : x
  2. Step 2: Convert to fraction form
    130.87/180.58 = 99.78/x
  3. Step 3: Cross multiply
    130.87x = 180.58 × 99.78
  4. Step 4: Simplify right side
    130.87x = 18,018.55
  5. Step 5: Solve for x
    x = 18,018.55/130.87
  6. Step 6: Final answer
    x = 137.69

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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.