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Finding the Fourth Proportional to 428.78, 643.62 and 377.75

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Solution

The fourth proportional to 428.78, 643.62 and 377.75 is: 567.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.78 : 643.62 = 377.75 : x
  2. Step 2: Convert to fraction form
    428.78/643.62 = 377.75/x
  3. Step 3: Cross multiply
    428.78x = 643.62 × 377.75
  4. Step 4: Simplify right side
    428.78x = 243,124.24
  5. Step 5: Solve for x
    x = 243,124.24/428.78
  6. Step 6: Final answer
    x = 567.02

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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.