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Finding the Fourth Proportional to 478.09, 659.79 and 312.74

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Solution

The fourth proportional to 478.09, 659.79 and 312.74 is: 431.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    478.09 : 659.79 = 312.74 : x
  2. Step 2: Convert to fraction form
    478.09/659.79 = 312.74/x
  3. Step 3: Cross multiply
    478.09x = 659.79 × 312.74
  4. Step 4: Simplify right side
    478.09x = 206,341.16
  5. Step 5: Solve for x
    x = 206,341.16/478.09
  6. Step 6: Final answer
    x = 431.60

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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.