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Finding the Fourth Proportional to 407.12, 561.78 and 257.56

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Solution

The fourth proportional to 407.12, 561.78 and 257.56 is: 355.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    407.12 : 561.78 = 257.56 : x
  2. Step 2: Convert to fraction form
    407.12/561.78 = 257.56/x
  3. Step 3: Cross multiply
    407.12x = 561.78 × 257.56
  4. Step 4: Simplify right side
    407.12x = 144,690.65
  5. Step 5: Solve for x
    x = 144,690.65/407.12
  6. Step 6: Final answer
    x = 355.40

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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.