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Finding the Fourth Proportional to 781.32, 1,171.16 and 312.62

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Solution

The fourth proportional to 781.32, 1,171.16 and 312.62 is: 468.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.32 : 1,171.16 = 312.62 : x
  2. Step 2: Convert to fraction form
    781.32/1,171.16 = 312.62/x
  3. Step 3: Cross multiply
    781.32x = 1,171.16 × 312.62
  4. Step 4: Simplify right side
    781.32x = 366,120.62
  5. Step 5: Solve for x
    x = 366,120.62/781.32
  6. Step 6: Final answer
    x = 468.59

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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.