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Finding the Fourth Proportional to 979.99, 1,470.36 and 431.78

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Solution

The fourth proportional to 979.99, 1,470.36 and 431.78 is: 647.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.99 : 1,470.36 = 431.78 : x
  2. Step 2: Convert to fraction form
    979.99/1,470.36 = 431.78/x
  3. Step 3: Cross multiply
    979.99x = 1,470.36 × 431.78
  4. Step 4: Simplify right side
    979.99x = 634,872.04
  5. Step 5: Solve for x
    x = 634,872.04/979.99
  6. Step 6: Final answer
    x = 647.84

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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.