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Finding the Fourth Proportional to 499.64, 690.05 and 381.78

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Solution

The fourth proportional to 499.64, 690.05 and 381.78 is: 527.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.64 : 690.05 = 381.78 : x
  2. Step 2: Convert to fraction form
    499.64/690.05 = 381.78/x
  3. Step 3: Cross multiply
    499.64x = 690.05 × 381.78
  4. Step 4: Simplify right side
    499.64x = 263,448.24
  5. Step 5: Solve for x
    x = 263,448.24/499.64
  6. Step 6: Final answer
    x = 527.28

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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.