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Finding the Fourth Proportional to 386.55, 533.21 and 312.75

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Solution

The fourth proportional to 386.55, 533.21 and 312.75 is: 431.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.55 : 533.21 = 312.75 : x
  2. Step 2: Convert to fraction form
    386.55/533.21 = 312.75/x
  3. Step 3: Cross multiply
    386.55x = 533.21 × 312.75
  4. Step 4: Simplify right side
    386.55x = 166,759.86
  5. Step 5: Solve for x
    x = 166,759.86/386.55
  6. Step 6: Final answer
    x = 431.41

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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.