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Finding the Fourth Proportional to 1,223.58, 1,688.10 and 781.44

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Solution

The fourth proportional to 1,223.58, 1,688.10 and 781.44 is: 1,078.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,223.58 : 1,688.10 = 781.44 : x
  2. Step 2: Convert to fraction form
    1,223.58/1,688.10 = 781.44/x
  3. Step 3: Cross multiply
    1,223.58x = 1,688.10 × 781.44
  4. Step 4: Simplify right side
    1,223.58x = 1,319,148.86
  5. Step 5: Solve for x
    x = 1,319,148.86/1,223.58
  6. Step 6: Final answer
    x = 1,078.11

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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.