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Finding the Fourth Proportional to 318.20, 438.14 and 305.07

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Solution

The fourth proportional to 318.20, 438.14 and 305.07 is: 420.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.20 : 438.14 = 305.07 : x
  2. Step 2: Convert to fraction form
    318.20/438.14 = 305.07/x
  3. Step 3: Cross multiply
    318.20x = 438.14 × 305.07
  4. Step 4: Simplify right side
    318.20x = 133,660.79
  5. Step 5: Solve for x
    x = 133,660.79/318.20
  6. Step 6: Final answer
    x = 420.05

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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.