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Finding the Fourth Proportional to 857.04, 1,285.68 and 279.78

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Solution

The fourth proportional to 857.04, 1,285.68 and 279.78 is: 419.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.04 : 1,285.68 = 279.78 : x
  2. Step 2: Convert to fraction form
    857.04/1,285.68 = 279.78/x
  3. Step 3: Cross multiply
    857.04x = 1,285.68 × 279.78
  4. Step 4: Simplify right side
    857.04x = 359,707.55
  5. Step 5: Solve for x
    x = 359,707.55/857.04
  6. Step 6: Final answer
    x = 419.71

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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.