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Finding the Fourth Proportional to 87.50, 120.84 and 86.90

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Solution

The fourth proportional to 87.50, 120.84 and 86.90 is: 120.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.50 : 120.84 = 86.90 : x
  2. Step 2: Convert to fraction form
    87.50/120.84 = 86.90/x
  3. Step 3: Cross multiply
    87.50x = 120.84 × 86.90
  4. Step 4: Simplify right side
    87.50x = 10,501.00
  5. Step 5: Solve for x
    x = 10,501.00/87.50
  6. Step 6: Final answer
    x = 120.01

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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.