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Finding the Fourth Proportional to 678.87, 939.30 and 591.74

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Solution

The fourth proportional to 678.87, 939.30 and 591.74 is: 818.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.87 : 939.30 = 591.74 : x
  2. Step 2: Convert to fraction form
    678.87/939.30 = 591.74/x
  3. Step 3: Cross multiply
    678.87x = 939.30 × 591.74
  4. Step 4: Simplify right side
    678.87x = 555,816.69
  5. Step 5: Solve for x
    x = 555,816.69/678.87
  6. Step 6: Final answer
    x = 818.74

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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.