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Finding the Fourth Proportional to 666.40, 999.76 and 319.64

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Solution

The fourth proportional to 666.40, 999.76 and 319.64 is: 479.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.40 : 999.76 = 319.64 : x
  2. Step 2: Convert to fraction form
    666.40/999.76 = 319.64/x
  3. Step 3: Cross multiply
    666.40x = 999.76 × 319.64
  4. Step 4: Simplify right side
    666.40x = 319,563.29
  5. Step 5: Solve for x
    x = 319,563.29/666.40
  6. Step 6: Final answer
    x = 479.54

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.