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Finding the Fourth Proportional to 645.15, 891.66 and 488.31

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Solution

The fourth proportional to 645.15, 891.66 and 488.31 is: 674.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.15 : 891.66 = 488.31 : x
  2. Step 2: Convert to fraction form
    645.15/891.66 = 488.31/x
  3. Step 3: Cross multiply
    645.15x = 891.66 × 488.31
  4. Step 4: Simplify right side
    645.15x = 435,406.49
  5. Step 5: Solve for x
    x = 435,406.49/645.15
  6. Step 6: Final answer
    x = 674.89

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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.