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Finding the Fourth Proportional to 281.10, 420.78 and 257.18

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Solution

The fourth proportional to 281.10, 420.78 and 257.18 is: 384.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.10 : 420.78 = 257.18 : x
  2. Step 2: Convert to fraction form
    281.10/420.78 = 257.18/x
  3. Step 3: Cross multiply
    281.10x = 420.78 × 257.18
  4. Step 4: Simplify right side
    281.10x = 108,212.81
  5. Step 5: Solve for x
    x = 108,212.81/281.10
  6. Step 6: Final answer
    x = 384.96

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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.