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Finding the Fourth Proportional to 6.40, 9.72 and 6.40

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Solution

The fourth proportional to 6.40, 9.72 and 6.40 is: 9.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.40 : 9.72 = 6.40 : x
  2. Step 2: Convert to fraction form
    6.40/9.72 = 6.40/x
  3. Step 3: Cross multiply
    6.40x = 9.72 × 6.40
  4. Step 4: Simplify right side
    6.40x = 62.21
  5. Step 5: Solve for x
    x = 62.21/6.40
  6. Step 6: Final answer
    x = 9.72

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Why These Related Problems?

These problems maintain the same ratio (1.52) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.