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Finding the Fourth Proportional to 72.21, 99.76 and 66.74

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Solution

The fourth proportional to 72.21, 99.76 and 66.74 is: 92.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.21 : 99.76 = 66.74 : x
  2. Step 2: Convert to fraction form
    72.21/99.76 = 66.74/x
  3. Step 3: Cross multiply
    72.21x = 99.76 × 66.74
  4. Step 4: Simplify right side
    72.21x = 6,658.06
  5. Step 5: Solve for x
    x = 6,658.06/72.21
  6. Step 6: Final answer
    x = 92.20

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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.