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Finding the Fourth Proportional to 30.90, 46.35 and 12.86

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Solution

The fourth proportional to 30.90, 46.35 and 12.86 is: 19.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.90 : 46.35 = 12.86 : x
  2. Step 2: Convert to fraction form
    30.90/46.35 = 12.86/x
  3. Step 3: Cross multiply
    30.90x = 46.35 × 12.86
  4. Step 4: Simplify right side
    30.90x = 596.06
  5. Step 5: Solve for x
    x = 596.06/30.90
  6. Step 6: Final answer
    x = 19.29

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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.