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Finding the Fourth Proportional to 645.80, 891.29 and 397.16

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Solution

The fourth proportional to 645.80, 891.29 and 397.16 is: 548.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.80 : 891.29 = 397.16 : x
  2. Step 2: Convert to fraction form
    645.80/891.29 = 397.16/x
  3. Step 3: Cross multiply
    645.80x = 891.29 × 397.16
  4. Step 4: Simplify right side
    645.80x = 353,978.29
  5. Step 5: Solve for x
    x = 353,978.29/645.80
  6. Step 6: Final answer
    x = 548.12

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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.