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Finding the Fourth Proportional to 72.18, 100.02 and 70.81

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Solution

The fourth proportional to 72.18, 100.02 and 70.81 is: 98.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.18 : 100.02 = 70.81 : x
  2. Step 2: Convert to fraction form
    72.18/100.02 = 70.81/x
  3. Step 3: Cross multiply
    72.18x = 100.02 × 70.81
  4. Step 4: Simplify right side
    72.18x = 7,081.92
  5. Step 5: Solve for x
    x = 7,081.92/72.18
  6. Step 6: Final answer
    x = 98.12

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.