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Finding the Fourth Proportional to 505.45, 697.20 and 318.88

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Solution

The fourth proportional to 505.45, 697.20 and 318.88 is: 439.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    505.45 : 697.20 = 318.88 : x
  2. Step 2: Convert to fraction form
    505.45/697.20 = 318.88/x
  3. Step 3: Cross multiply
    505.45x = 697.20 × 318.88
  4. Step 4: Simplify right side
    505.45x = 222,323.14
  5. Step 5: Solve for x
    x = 222,323.14/505.45
  6. Step 6: Final answer
    x = 439.85

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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.