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Finding the Fourth Proportional to 105.30, 145.20 and 72.57

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Solution

The fourth proportional to 105.30, 145.20 and 72.57 is: 100.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.30 : 145.20 = 72.57 : x
  2. Step 2: Convert to fraction form
    105.30/145.20 = 72.57/x
  3. Step 3: Cross multiply
    105.30x = 145.20 × 72.57
  4. Step 4: Simplify right side
    105.30x = 10,537.16
  5. Step 5: Solve for x
    x = 10,537.16/105.30
  6. Step 6: Final answer
    x = 100.07

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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.