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Finding the Fourth Proportional to 999.32, 1,378.97 and 645.76

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Solution

The fourth proportional to 999.32, 1,378.97 and 645.76 is: 891.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.32 : 1,378.97 = 645.76 : x
  2. Step 2: Convert to fraction form
    999.32/1,378.97 = 645.76/x
  3. Step 3: Cross multiply
    999.32x = 1,378.97 × 645.76
  4. Step 4: Simplify right side
    999.32x = 890,483.67
  5. Step 5: Solve for x
    x = 890,483.67/999.32
  6. Step 6: Final answer
    x = 891.09

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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.