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Finding the Fourth Proportional to 389.81, 538.25 and 312.53

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Solution

The fourth proportional to 389.81, 538.25 and 312.53 is: 431.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.81 : 538.25 = 312.53 : x
  2. Step 2: Convert to fraction form
    389.81/538.25 = 312.53/x
  3. Step 3: Cross multiply
    389.81x = 538.25 × 312.53
  4. Step 4: Simplify right side
    389.81x = 168,219.27
  5. Step 5: Solve for x
    x = 168,219.27/389.81
  6. Step 6: Final answer
    x = 431.54

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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.