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Finding the Fourth Proportional to 428.32, 643.74 and 355.66

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Solution

The fourth proportional to 428.32, 643.74 and 355.66 is: 534.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.32 : 643.74 = 355.66 : x
  2. Step 2: Convert to fraction form
    428.32/643.74 = 355.66/x
  3. Step 3: Cross multiply
    428.32x = 643.74 × 355.66
  4. Step 4: Simplify right side
    428.32x = 228,955.25
  5. Step 5: Solve for x
    x = 228,955.25/428.32
  6. Step 6: Final answer
    x = 534.54

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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.