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Finding the Fourth Proportional to 509.78, 703.48 and 288.72

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Solution

The fourth proportional to 509.78, 703.48 and 288.72 is: 398.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    509.78 : 703.48 = 288.72 : x
  2. Step 2: Convert to fraction form
    509.78/703.48 = 288.72/x
  3. Step 3: Cross multiply
    509.78x = 703.48 × 288.72
  4. Step 4: Simplify right side
    509.78x = 203,108.75
  5. Step 5: Solve for x
    x = 203,108.75/509.78
  6. Step 6: Final answer
    x = 398.42

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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.