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Finding the Fourth Proportional to 72.90, 109.40 and 40.40

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Solution

The fourth proportional to 72.90, 109.40 and 40.40 is: 60.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.90 : 109.40 = 40.40 : x
  2. Step 2: Convert to fraction form
    72.90/109.40 = 40.40/x
  3. Step 3: Cross multiply
    72.90x = 109.40 × 40.40
  4. Step 4: Simplify right side
    72.90x = 4,419.76
  5. Step 5: Solve for x
    x = 4,419.76/72.90
  6. Step 6: Final answer
    x = 60.63

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.