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Finding the Fourth Proportional to 478.38, 659.64 and 312.60

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Solution

The fourth proportional to 478.38, 659.64 and 312.60 is: 431.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.38 : 659.64 = 312.60 : x
  2. Step 2: Convert to fraction form
    478.38/659.64 = 312.60/x
  3. Step 3: Cross multiply
    478.38x = 659.64 × 312.60
  4. Step 4: Simplify right side
    478.38x = 206,203.46
  5. Step 5: Solve for x
    x = 206,203.46/478.38
  6. Step 6: Final answer
    x = 431.05

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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.