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Finding the Fourth Proportional to 130.86, 180.45 and 87.12

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Solution

The fourth proportional to 130.86, 180.45 and 87.12 is: 120.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    130.86 : 180.45 = 87.12 : x
  2. Step 2: Convert to fraction form
    130.86/180.45 = 87.12/x
  3. Step 3: Cross multiply
    130.86x = 180.45 × 87.12
  4. Step 4: Simplify right side
    130.86x = 15,720.80
  5. Step 5: Solve for x
    x = 15,720.80/130.86
  6. Step 6: Final answer
    x = 120.13

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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.