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Finding the Fourth Proportional to 72.75, 100.39 and 40

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Solution

The fourth proportional to 72.75, 100.39 and 40 is: 55.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.75 : 100.39 = 40 : x
  2. Step 2: Convert to fraction form
    72.75/100.39 = 40/x
  3. Step 3: Cross multiply
    72.75x = 100.39 × 40
  4. Step 4: Simplify right side
    72.75x = 4,015.60
  5. Step 5: Solve for x
    x = 4,015.60/72.75
  6. Step 6: Final answer
    x = 55.20

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1.5x scale

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.