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Finding the Fourth Proportional to 645.64, 890.72 and 393.32

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Solution

The fourth proportional to 645.64, 890.72 and 393.32 is: 542.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.64 : 890.72 = 393.32 : x
  2. Step 2: Convert to fraction form
    645.64/890.72 = 393.32/x
  3. Step 3: Cross multiply
    645.64x = 890.72 × 393.32
  4. Step 4: Simplify right side
    645.64x = 350,337.99
  5. Step 5: Solve for x
    x = 350,337.99/645.64
  6. Step 6: Final answer
    x = 542.62

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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.