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Finding the Fourth Proportional to 72.05, 99.47 and 64.25

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Solution

The fourth proportional to 72.05, 99.47 and 64.25 is: 88.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.05 : 99.47 = 64.25 : x
  2. Step 2: Convert to fraction form
    72.05/99.47 = 64.25/x
  3. Step 3: Cross multiply
    72.05x = 99.47 × 64.25
  4. Step 4: Simplify right side
    72.05x = 6,390.13
  5. Step 5: Solve for x
    x = 6,390.13/72.05
  6. Step 6: Final answer
    x = 88.70

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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.