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Finding the Fourth Proportional to 665.74, 918.78 and 403.90

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Solution

The fourth proportional to 665.74, 918.78 and 403.90 is: 557.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.74 : 918.78 = 403.90 : x
  2. Step 2: Convert to fraction form
    665.74/918.78 = 403.90/x
  3. Step 3: Cross multiply
    665.74x = 918.78 × 403.90
  4. Step 4: Simplify right side
    665.74x = 371,095.24
  5. Step 5: Solve for x
    x = 371,095.24/665.74
  6. Step 6: Final answer
    x = 557.42

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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.