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Finding the Fourth Proportional to 4.85, 6.65 and 4.78

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Solution

The fourth proportional to 4.85, 6.65 and 4.78 is: 6.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    4.85 : 6.65 = 4.78 : x
  2. Step 2: Convert to fraction form
    4.85/6.65 = 4.78/x
  3. Step 3: Cross multiply
    4.85x = 6.65 × 4.78
  4. Step 4: Simplify right side
    4.85x = 31.79
  5. Step 5: Solve for x
    x = 31.79/4.85
  6. Step 6: Final answer
    x = 6.55

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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.