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Finding the Fourth Proportional to 709.88, 979.76 and 678.74

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Solution

The fourth proportional to 709.88, 979.76 and 678.74 is: 936.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.88 : 979.76 = 678.74 : x
  2. Step 2: Convert to fraction form
    709.88/979.76 = 678.74/x
  3. Step 3: Cross multiply
    709.88x = 979.76 × 678.74
  4. Step 4: Simplify right side
    709.88x = 665,000.79
  5. Step 5: Solve for x
    x = 665,000.79/709.88
  6. Step 6: Final answer
    x = 936.79

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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.