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Finding the Fourth Proportional to 389.65, 538.27 and 311.48

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Solution

The fourth proportional to 389.65, 538.27 and 311.48 is: 430.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.65 : 538.27 = 311.48 : x
  2. Step 2: Convert to fraction form
    389.65/538.27 = 311.48/x
  3. Step 3: Cross multiply
    389.65x = 538.27 × 311.48
  4. Step 4: Simplify right side
    389.65x = 167,660.91
  5. Step 5: Solve for x
    x = 167,660.91/389.65
  6. Step 6: Final answer
    x = 430.29

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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.