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Finding the Fourth Proportional to 428.36, 640.04 and 316.71

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Solution

The fourth proportional to 428.36, 640.04 and 316.71 is: 473.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.36 : 640.04 = 316.71 : x
  2. Step 2: Convert to fraction form
    428.36/640.04 = 316.71/x
  3. Step 3: Cross multiply
    428.36x = 640.04 × 316.71
  4. Step 4: Simplify right side
    428.36x = 202,704.12
  5. Step 5: Solve for x
    x = 202,704.12/428.36
  6. Step 6: Final answer
    x = 473.21

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.