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Finding the Fourth Proportional to 499.64, 689.38 and 289.78

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Solution

The fourth proportional to 499.64, 689.38 and 289.78 is: 399.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.64 : 689.38 = 289.78 : x
  2. Step 2: Convert to fraction form
    499.64/689.38 = 289.78/x
  3. Step 3: Cross multiply
    499.64x = 689.38 × 289.78
  4. Step 4: Simplify right side
    499.64x = 199,766.09
  5. Step 5: Solve for x
    x = 199,766.09/499.64
  6. Step 6: Final answer
    x = 399.82

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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.