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Finding the Fourth Proportional to 997.78, 1,376.90 and 555.65

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Solution

The fourth proportional to 997.78, 1,376.90 and 555.65 is: 766.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    997.78 : 1,376.90 = 555.65 : x
  2. Step 2: Convert to fraction form
    997.78/1,376.90 = 555.65/x
  3. Step 3: Cross multiply
    997.78x = 1,376.90 × 555.65
  4. Step 4: Simplify right side
    997.78x = 765,071.71
  5. Step 5: Solve for x
    x = 765,071.71/997.78
  6. Step 6: Final answer
    x = 766.78

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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.