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Finding the Fourth Proportional to 427.29, 639.72 and 317.40

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Solution

The fourth proportional to 427.29, 639.72 and 317.40 is: 475.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.29 : 639.72 = 317.40 : x
  2. Step 2: Convert to fraction form
    427.29/639.72 = 317.40/x
  3. Step 3: Cross multiply
    427.29x = 639.72 × 317.40
  4. Step 4: Simplify right side
    427.29x = 203,047.13
  5. Step 5: Solve for x
    x = 203,047.13/427.29
  6. Step 6: Final answer
    x = 475.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.