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Finding the Fourth Proportional to 105.78, 145.86 and 79.50

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Solution

The fourth proportional to 105.78, 145.86 and 79.50 is: 109.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.78 : 145.86 = 79.50 : x
  2. Step 2: Convert to fraction form
    105.78/145.86 = 79.50/x
  3. Step 3: Cross multiply
    105.78x = 145.86 × 79.50
  4. Step 4: Simplify right side
    105.78x = 11,595.87
  5. Step 5: Solve for x
    x = 11,595.87/105.78
  6. Step 6: Final answer
    x = 109.62

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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.