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Finding the Fourth Proportional to 1,223.85, 1,688.90 and 699.78

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Solution

The fourth proportional to 1,223.85, 1,688.90 and 699.78 is: 965.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,223.85 : 1,688.90 = 699.78 : x
  2. Step 2: Convert to fraction form
    1,223.85/1,688.90 = 699.78/x
  3. Step 3: Cross multiply
    1,223.85x = 1,688.90 × 699.78
  4. Step 4: Simplify right side
    1,223.85x = 1,181,854.94
  5. Step 5: Solve for x
    x = 1,181,854.94/1,223.85
  6. Step 6: Final answer
    x = 965.69

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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.