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Finding the Fourth Proportional to 857.70, 1,281.72 and 638.82

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Solution

The fourth proportional to 857.70, 1,281.72 and 638.82 is: 954.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.70 : 1,281.72 = 638.82 : x
  2. Step 2: Convert to fraction form
    857.70/1,281.72 = 638.82/x
  3. Step 3: Cross multiply
    857.70x = 1,281.72 × 638.82
  4. Step 4: Simplify right side
    857.70x = 818,788.37
  5. Step 5: Solve for x
    x = 818,788.37/857.70
  6. Step 6: Final answer
    x = 954.63

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.