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Finding the Fourth Proportional to 105.40, 145.40 and 72.59

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Solution

The fourth proportional to 105.40, 145.40 and 72.59 is: 100.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.40 : 145.40 = 72.59 : x
  2. Step 2: Convert to fraction form
    105.40/145.40 = 72.59/x
  3. Step 3: Cross multiply
    105.40x = 145.40 × 72.59
  4. Step 4: Simplify right side
    105.40x = 10,554.59
  5. Step 5: Solve for x
    x = 10,554.59/105.40
  6. Step 6: Final answer
    x = 100.14

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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.