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Finding the Fourth Proportional to 772.80, 1,158.75 and 285.90

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Solution

The fourth proportional to 772.80, 1,158.75 and 285.90 is: 428.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    772.80 : 1,158.75 = 285.90 : x
  2. Step 2: Convert to fraction form
    772.80/1,158.75 = 285.90/x
  3. Step 3: Cross multiply
    772.80x = 1,158.75 × 285.90
  4. Step 4: Simplify right side
    772.80x = 331,286.63
  5. Step 5: Solve for x
    x = 331,286.63/772.80
  6. Step 6: Final answer
    x = 428.68

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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.