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Finding the Fourth Proportional to 783.84, 1,081.40 and 489

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Solution

The fourth proportional to 783.84, 1,081.40 and 489 is: 674.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    783.84 : 1,081.40 = 489 : x
  2. Step 2: Convert to fraction form
    783.84/1,081.40 = 489/x
  3. Step 3: Cross multiply
    783.84x = 1,081.40 × 489
  4. Step 4: Simplify right side
    783.84x = 528,804.60
  5. Step 5: Solve for x
    x = 528,804.60/783.84
  6. Step 6: Final answer
    x = 674.63

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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.