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Finding the Fourth Proportional to 72.38, 99.90 and 70.31

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Solution

The fourth proportional to 72.38, 99.90 and 70.31 is: 97.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.38 : 99.90 = 70.31 : x
  2. Step 2: Convert to fraction form
    72.38/99.90 = 70.31/x
  3. Step 3: Cross multiply
    72.38x = 99.90 × 70.31
  4. Step 4: Simplify right side
    72.38x = 7,023.97
  5. Step 5: Solve for x
    x = 7,023.97/72.38
  6. Step 6: Final answer
    x = 97.04

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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.