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Finding the Fourth Proportional to 87.36, 130.90 and 79.86

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Solution

The fourth proportional to 87.36, 130.90 and 79.86 is: 119.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.36 : 130.90 = 79.86 : x
  2. Step 2: Convert to fraction form
    87.36/130.90 = 79.86/x
  3. Step 3: Cross multiply
    87.36x = 130.90 × 79.86
  4. Step 4: Simplify right side
    87.36x = 10,453.67
  5. Step 5: Solve for x
    x = 10,453.67/87.36
  6. Step 6: Final answer
    x = 119.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.