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Finding the Fourth Proportional to 999.72, 1,378.34 and 645.04

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Solution

The fourth proportional to 999.72, 1,378.34 and 645.04 is: 889.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.72 : 1,378.34 = 645.04 : x
  2. Step 2: Convert to fraction form
    999.72/1,378.34 = 645.04/x
  3. Step 3: Cross multiply
    999.72x = 1,378.34 × 645.04
  4. Step 4: Simplify right side
    999.72x = 889,083.29
  5. Step 5: Solve for x
    x = 889,083.29/999.72
  6. Step 6: Final answer
    x = 889.33

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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.