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Finding the Fourth Proportional to 696.78, 1,045.15 and 285.80

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Solution

The fourth proportional to 696.78, 1,045.15 and 285.80 is: 428.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    696.78 : 1,045.15 = 285.80 : x
  2. Step 2: Convert to fraction form
    696.78/1,045.15 = 285.80/x
  3. Step 3: Cross multiply
    696.78x = 1,045.15 × 285.80
  4. Step 4: Simplify right side
    696.78x = 298,703.87
  5. Step 5: Solve for x
    x = 298,703.87/696.78
  6. Step 6: Final answer
    x = 428.69

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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.