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Finding the Fourth Proportional to 999.72, 1,379.70 and 649.80

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Solution

The fourth proportional to 999.72, 1,379.70 and 649.80 is: 896.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.72 : 1,379.70 = 649.80 : x
  2. Step 2: Convert to fraction form
    999.72/1,379.70 = 649.80/x
  3. Step 3: Cross multiply
    999.72x = 1,379.70 × 649.80
  4. Step 4: Simplify right side
    999.72x = 896,529.06
  5. Step 5: Solve for x
    x = 896,529.06/999.72
  6. Step 6: Final answer
    x = 896.78

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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.