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Finding the Fourth Proportional to 428.52, 643.04 and 172

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Solution

The fourth proportional to 428.52, 643.04 and 172 is: 258.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.52 : 643.04 = 172 : x
  2. Step 2: Convert to fraction form
    428.52/643.04 = 172/x
  3. Step 3: Cross multiply
    428.52x = 643.04 × 172
  4. Step 4: Simplify right side
    428.52x = 110,602.88
  5. Step 5: Solve for x
    x = 110,602.88/428.52
  6. Step 6: Final answer
    x = 258.10

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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.