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Finding the Fourth Proportional to 666.42, 999.70 and 319.70

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Solution

The fourth proportional to 666.42, 999.70 and 319.70 is: 479.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.42 : 999.70 = 319.70 : x
  2. Step 2: Convert to fraction form
    666.42/999.70 = 319.70/x
  3. Step 3: Cross multiply
    666.42x = 999.70 × 319.70
  4. Step 4: Simplify right side
    666.42x = 319,604.09
  5. Step 5: Solve for x
    x = 319,604.09/666.42
  6. Step 6: Final answer
    x = 479.58

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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.