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Finding the Fourth Proportional to 499.78, 689.69 and 278.72

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Solution

The fourth proportional to 499.78, 689.69 and 278.72 is: 384.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    499.78 : 689.69 = 278.72 : x
  2. Step 2: Convert to fraction form
    499.78/689.69 = 278.72/x
  3. Step 3: Cross multiply
    499.78x = 689.69 × 278.72
  4. Step 4: Simplify right side
    499.78x = 192,230.40
  5. Step 5: Solve for x
    x = 192,230.40/499.78
  6. Step 6: Final answer
    x = 384.63

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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.