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Finding the Fourth Proportional to 905.78, 1,358.40 and 385.77

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Solution

The fourth proportional to 905.78, 1,358.40 and 385.77 is: 578.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    905.78 : 1,358.40 = 385.77 : x
  2. Step 2: Convert to fraction form
    905.78/1,358.40 = 385.77/x
  3. Step 3: Cross multiply
    905.78x = 1,358.40 × 385.77
  4. Step 4: Simplify right side
    905.78x = 524,033.36
  5. Step 5: Solve for x
    x = 524,033.36/905.78
  6. Step 6: Final answer
    x = 578.55

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Double scale
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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.