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Finding the Fourth Proportional to 912.88, 1,369.20 and 393

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Solution

The fourth proportional to 912.88, 1,369.20 and 393 is: 589.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    912.88 : 1,369.20 = 393 : x
  2. Step 2: Convert to fraction form
    912.88/1,369.20 = 393/x
  3. Step 3: Cross multiply
    912.88x = 1,369.20 × 393
  4. Step 4: Simplify right side
    912.88x = 538,095.60
  5. Step 5: Solve for x
    x = 538,095.60/912.88
  6. Step 6: Final answer
    x = 589.45

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Double scale
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Similar ratio
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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.