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Finding the Fourth Proportional to 407.21, 561.78 and 276.57

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Solution

The fourth proportional to 407.21, 561.78 and 276.57 is: 381.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    407.21 : 561.78 = 276.57 : x
  2. Step 2: Convert to fraction form
    407.21/561.78 = 276.57/x
  3. Step 3: Cross multiply
    407.21x = 561.78 × 276.57
  4. Step 4: Simplify right side
    407.21x = 155,371.49
  5. Step 5: Solve for x
    x = 155,371.49/407.21
  6. Step 6: Final answer
    x = 381.56

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.