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Finding the Fourth Proportional to 1,212.78, 1,673.67 and 688.80

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Solution

The fourth proportional to 1,212.78, 1,673.67 and 688.80 is: 950.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.78 : 1,673.67 = 688.80 : x
  2. Step 2: Convert to fraction form
    1,212.78/1,673.67 = 688.80/x
  3. Step 3: Cross multiply
    1,212.78x = 1,673.67 × 688.80
  4. Step 4: Simplify right side
    1,212.78x = 1,152,823.90
  5. Step 5: Solve for x
    x = 1,152,823.90/1,212.78
  6. Step 6: Final answer
    x = 950.56

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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.