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Finding the Fourth Proportional to 645.12, 890 and 382.88

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Solution

The fourth proportional to 645.12, 890 and 382.88 is: 528.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.12 : 890 = 382.88 : x
  2. Step 2: Convert to fraction form
    645.12/890 = 382.88/x
  3. Step 3: Cross multiply
    645.12x = 890 × 382.88
  4. Step 4: Simplify right side
    645.12x = 340,763.20
  5. Step 5: Solve for x
    x = 340,763.20/645.12
  6. Step 6: Final answer
    x = 528.22

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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.