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Finding the Fourth Proportional to 6.42, 8.80 and 6.40

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Solution

The fourth proportional to 6.42, 8.80 and 6.40 is: 8.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.42 : 8.80 = 6.40 : x
  2. Step 2: Convert to fraction form
    6.42/8.80 = 6.40/x
  3. Step 3: Cross multiply
    6.42x = 8.80 × 6.40
  4. Step 4: Simplify right side
    6.42x = 56.33
  5. Step 5: Solve for x
    x = 56.33/6.42
  6. Step 6: Final answer
    x = 8.78

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.