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Finding the Fourth Proportional to 72.36, 99.90 and 65.82

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Solution

The fourth proportional to 72.36, 99.90 and 65.82 is: 90.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.36 : 99.90 = 65.82 : x
  2. Step 2: Convert to fraction form
    72.36/99.90 = 65.82/x
  3. Step 3: Cross multiply
    72.36x = 99.90 × 65.82
  4. Step 4: Simplify right side
    72.36x = 6,575.42
  5. Step 5: Solve for x
    x = 6,575.42/72.36
  6. Step 6: Final answer
    x = 90.87

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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.