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Finding the Fourth Proportional to 475.78, 709.40 and 428.59

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Solution

The fourth proportional to 475.78, 709.40 and 428.59 is: 639.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    475.78 : 709.40 = 428.59 : x
  2. Step 2: Convert to fraction form
    475.78/709.40 = 428.59/x
  3. Step 3: Cross multiply
    475.78x = 709.40 × 428.59
  4. Step 4: Simplify right side
    475.78x = 304,041.75
  5. Step 5: Solve for x
    x = 304,041.75/475.78
  6. Step 6: Final answer
    x = 639.04

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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.