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Finding the Fourth Proportional to 70.20, 97.40 and 64.80

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Solution

The fourth proportional to 70.20, 97.40 and 64.80 is: 89.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.20 : 97.40 = 64.80 : x
  2. Step 2: Convert to fraction form
    70.20/97.40 = 64.80/x
  3. Step 3: Cross multiply
    70.20x = 97.40 × 64.80
  4. Step 4: Simplify right side
    70.20x = 6,311.52
  5. Step 5: Solve for x
    x = 6,311.52/70.20
  6. Step 6: Final answer
    x = 89.91

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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.