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Finding the Fourth Proportional to 823.67, 1,236 and 390.86

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Solution

The fourth proportional to 823.67, 1,236 and 390.86 is: 586.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    823.67 : 1,236 = 390.86 : x
  2. Step 2: Convert to fraction form
    823.67/1,236 = 390.86/x
  3. Step 3: Cross multiply
    823.67x = 1,236 × 390.86
  4. Step 4: Simplify right side
    823.67x = 483,102.96
  5. Step 5: Solve for x
    x = 483,102.96/823.67
  6. Step 6: Final answer
    x = 586.52

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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.