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Finding the Fourth Proportional to 1,108, 1,529.10 and 642.40

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Solution

The fourth proportional to 1,108, 1,529.10 and 642.40 is: 886.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,108 : 1,529.10 = 642.40 : x
  2. Step 2: Convert to fraction form
    1,108/1,529.10 = 642.40/x
  3. Step 3: Cross multiply
    1,108x = 1,529.10 × 642.40
  4. Step 4: Simplify right side
    1,108x = 982,293.84
  5. Step 5: Solve for x
    x = 982,293.84/1,108
  6. Step 6: Final answer
    x = 886.55

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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.