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Finding the Fourth Proportional to 639.15, 882.45 and 491.52

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Solution

The fourth proportional to 639.15, 882.45 and 491.52 is: 678.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    639.15 : 882.45 = 491.52 : x
  2. Step 2: Convert to fraction form
    639.15/882.45 = 491.52/x
  3. Step 3: Cross multiply
    639.15x = 882.45 × 491.52
  4. Step 4: Simplify right side
    639.15x = 433,741.82
  5. Step 5: Solve for x
    x = 433,741.82/639.15
  6. Step 6: Final answer
    x = 678.62

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.