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Finding the Fourth Proportional to 72.25, 99.70 and 39.50

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Solution

The fourth proportional to 72.25, 99.70 and 39.50 is: 54.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.25 : 99.70 = 39.50 : x
  2. Step 2: Convert to fraction form
    72.25/99.70 = 39.50/x
  3. Step 3: Cross multiply
    72.25x = 99.70 × 39.50
  4. Step 4: Simplify right side
    72.25x = 3,938.23
  5. Step 5: Solve for x
    x = 3,938.23/72.25
  6. Step 6: Final answer
    x = 54.51

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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.