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Finding the Fourth Proportional to 1,091.84, 1,638.40 and 408.32

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Solution

The fourth proportional to 1,091.84, 1,638.40 and 408.32 is: 612.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,091.84 : 1,638.40 = 408.32 : x
  2. Step 2: Convert to fraction form
    1,091.84/1,638.40 = 408.32/x
  3. Step 3: Cross multiply
    1,091.84x = 1,638.40 × 408.32
  4. Step 4: Simplify right side
    1,091.84x = 668,991.49
  5. Step 5: Solve for x
    x = 668,991.49/1,091.84
  6. Step 6: Final answer
    x = 612.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.