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Finding the Fourth Proportional to 999.72, 1,380.15 and 668.64

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Solution

The fourth proportional to 999.72, 1,380.15 and 668.64 is: 923.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    999.72 : 1,380.15 = 668.64 : x
  2. Step 2: Convert to fraction form
    999.72/1,380.15 = 668.64/x
  3. Step 3: Cross multiply
    999.72x = 1,380.15 × 668.64
  4. Step 4: Simplify right side
    999.72x = 922,823.50
  5. Step 5: Solve for x
    x = 922,823.50/999.72
  6. Step 6: Final answer
    x = 923.08

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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.