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Finding the Fourth Proportional to 399.32, 549.12 and 319.64

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Solution

The fourth proportional to 399.32, 549.12 and 319.64 is: 439.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.32 : 549.12 = 319.64 : x
  2. Step 2: Convert to fraction form
    399.32/549.12 = 319.64/x
  3. Step 3: Cross multiply
    399.32x = 549.12 × 319.64
  4. Step 4: Simplify right side
    399.32x = 175,517.97
  5. Step 5: Solve for x
    x = 175,517.97/399.32
  6. Step 6: Final answer
    x = 439.55

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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.