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Finding the Fourth Proportional to 645.68, 890.95 and 409.21

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Solution

The fourth proportional to 645.68, 890.95 and 409.21 is: 564.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.68 : 890.95 = 409.21 : x
  2. Step 2: Convert to fraction form
    645.68/890.95 = 409.21/x
  3. Step 3: Cross multiply
    645.68x = 890.95 × 409.21
  4. Step 4: Simplify right side
    645.68x = 364,586.67
  5. Step 5: Solve for x
    x = 364,586.67/645.68
  6. Step 6: Final answer
    x = 564.66

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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.