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Finding the Fourth Proportional to 784.42, 1,081.62 and 489.30

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Solution

The fourth proportional to 784.42, 1,081.62 and 489.30 is: 674.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    784.42 : 1,081.62 = 489.30 : x
  2. Step 2: Convert to fraction form
    784.42/1,081.62 = 489.30/x
  3. Step 3: Cross multiply
    784.42x = 1,081.62 × 489.30
  4. Step 4: Simplify right side
    784.42x = 529,236.67
  5. Step 5: Solve for x
    x = 529,236.67/784.42
  6. Step 6: Final answer
    x = 674.69

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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.