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Finding the Fourth Proportional to 113.54, 156.65 and 78.64

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Solution

The fourth proportional to 113.54, 156.65 and 78.64 is: 108.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    113.54 : 156.65 = 78.64 : x
  2. Step 2: Convert to fraction form
    113.54/156.65 = 78.64/x
  3. Step 3: Cross multiply
    113.54x = 156.65 × 78.64
  4. Step 4: Simplify right side
    113.54x = 12,318.17
  5. Step 5: Solve for x
    x = 12,318.17/113.54
  6. Step 6: Final answer
    x = 108.50

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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.