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Finding the Fourth Proportional to 428.89, 643.32 and 284.71

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Solution

The fourth proportional to 428.89, 643.32 and 284.71 is: 427.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.89 : 643.32 = 284.71 : x
  2. Step 2: Convert to fraction form
    428.89/643.32 = 284.71/x
  3. Step 3: Cross multiply
    428.89x = 643.32 × 284.71
  4. Step 4: Simplify right side
    428.89x = 183,159.64
  5. Step 5: Solve for x
    x = 183,159.64/428.89
  6. Step 6: Final answer
    x = 427.06

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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.