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Finding the Fourth Proportional to 645.05, 889.87 and 379.40

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Solution

The fourth proportional to 645.05, 889.87 and 379.40 is: 523.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.05 : 889.87 = 379.40 : x
  2. Step 2: Convert to fraction form
    645.05/889.87 = 379.40/x
  3. Step 3: Cross multiply
    645.05x = 889.87 × 379.40
  4. Step 4: Simplify right side
    645.05x = 337,617.95
  5. Step 5: Solve for x
    x = 337,617.95/645.05
  6. Step 6: Final answer
    x = 523.40

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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.