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Finding the Fourth Proportional to 257.10, 385.61 and 74.45

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Solution

The fourth proportional to 257.10, 385.61 and 74.45 is: 111.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.10 : 385.61 = 74.45 : x
  2. Step 2: Convert to fraction form
    257.10/385.61 = 74.45/x
  3. Step 3: Cross multiply
    257.10x = 385.61 × 74.45
  4. Step 4: Simplify right side
    257.10x = 28,709.26
  5. Step 5: Solve for x
    x = 28,709.26/257.10
  6. Step 6: Final answer
    x = 111.67

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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.