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Finding the Fourth Proportional to 87.40, 130.80 and 65.72

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Solution

The fourth proportional to 87.40, 130.80 and 65.72 is: 98.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.40 : 130.80 = 65.72 : x
  2. Step 2: Convert to fraction form
    87.40/130.80 = 65.72/x
  3. Step 3: Cross multiply
    87.40x = 130.80 × 65.72
  4. Step 4: Simplify right side
    87.40x = 8,596.18
  5. Step 5: Solve for x
    x = 8,596.18/87.40
  6. Step 6: Final answer
    x = 98.35

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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.