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Finding the Fourth Proportional to 113.30, 156.43 and 78.31

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Solution

The fourth proportional to 113.30, 156.43 and 78.31 is: 108.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    113.30 : 156.43 = 78.31 : x
  2. Step 2: Convert to fraction form
    113.30/156.43 = 78.31/x
  3. Step 3: Cross multiply
    113.30x = 156.43 × 78.31
  4. Step 4: Simplify right side
    113.30x = 12,249.25
  5. Step 5: Solve for x
    x = 12,249.25/113.30
  6. Step 6: Final answer
    x = 108.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.