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Finding the Fourth Proportional to 663.35, 913.49 and 621.09

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Solution

The fourth proportional to 663.35, 913.49 and 621.09 is: 855.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.35 : 913.49 = 621.09 : x
  2. Step 2: Convert to fraction form
    663.35/913.49 = 621.09/x
  3. Step 3: Cross multiply
    663.35x = 913.49 × 621.09
  4. Step 4: Simplify right side
    663.35x = 567,359.50
  5. Step 5: Solve for x
    x = 567,359.50/663.35
  6. Step 6: Final answer
    x = 855.29

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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.