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Finding the Fourth Proportional to 665.21, 917.98 and 455.38

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Solution

The fourth proportional to 665.21, 917.98 and 455.38 is: 628.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.21 : 917.98 = 455.38 : x
  2. Step 2: Convert to fraction form
    665.21/917.98 = 455.38/x
  3. Step 3: Cross multiply
    665.21x = 917.98 × 455.38
  4. Step 4: Simplify right side
    665.21x = 418,032.74
  5. Step 5: Solve for x
    x = 418,032.74/665.21
  6. Step 6: Final answer
    x = 628.42

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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.