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Finding the Fourth Proportional to 407.18, 561.74 and 257.78

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Solution

The fourth proportional to 407.18, 561.74 and 257.78 is: 355.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    407.18 : 561.74 = 257.78 : x
  2. Step 2: Convert to fraction form
    407.18/561.74 = 257.78/x
  3. Step 3: Cross multiply
    407.18x = 561.74 × 257.78
  4. Step 4: Simplify right side
    407.18x = 144,805.45
  5. Step 5: Solve for x
    x = 144,805.45/407.18
  6. Step 6: Final answer
    x = 355.63

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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.