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Finding the Fourth Proportional to 561.74, 842.40 and 388.40

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Solution

The fourth proportional to 561.74, 842.40 and 388.40 is: 582.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    561.74 : 842.40 = 388.40 : x
  2. Step 2: Convert to fraction form
    561.74/842.40 = 388.40/x
  3. Step 3: Cross multiply
    561.74x = 842.40 × 388.40
  4. Step 4: Simplify right side
    561.74x = 327,183.95
  5. Step 5: Solve for x
    x = 327,183.95/561.74
  6. Step 6: Final answer
    x = 582.45

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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.