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Finding the Fourth Proportional to 689.86, 1,034.78 and 278.99

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Solution

The fourth proportional to 689.86, 1,034.78 and 278.99 is: 418.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.86 : 1,034.78 = 278.99 : x
  2. Step 2: Convert to fraction form
    689.86/1,034.78 = 278.99/x
  3. Step 3: Cross multiply
    689.86x = 1,034.78 × 278.99
  4. Step 4: Simplify right side
    689.86x = 288,690.58
  5. Step 5: Solve for x
    x = 288,690.58/689.86
  6. Step 6: Final answer
    x = 418.48

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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.