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Finding the Fourth Proportional to 645.71, 891.09 and 396.98

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Solution

The fourth proportional to 645.71, 891.09 and 396.98 is: 547.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.71 : 891.09 = 396.98 : x
  2. Step 2: Convert to fraction form
    645.71/891.09 = 396.98/x
  3. Step 3: Cross multiply
    645.71x = 891.09 × 396.98
  4. Step 4: Simplify right side
    645.71x = 353,742.40
  5. Step 5: Solve for x
    x = 353,742.40/645.71
  6. Step 6: Final answer
    x = 547.84

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.