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Finding the Fourth Proportional to 71.20, 98.68 and 64

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Solution

The fourth proportional to 71.20, 98.68 and 64 is: 88.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.20 : 98.68 = 64 : x
  2. Step 2: Convert to fraction form
    71.20/98.68 = 64/x
  3. Step 3: Cross multiply
    71.20x = 98.68 × 64
  4. Step 4: Simplify right side
    71.20x = 6,315.52
  5. Step 5: Solve for x
    x = 6,315.52/71.20
  6. Step 6: Final answer
    x = 88.70

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.