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Finding the Fourth Proportional to 72.99, 109.29 and 66.60

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Solution

The fourth proportional to 72.99, 109.29 and 66.60 is: 99.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.99 : 109.29 = 66.60 : x
  2. Step 2: Convert to fraction form
    72.99/109.29 = 66.60/x
  3. Step 3: Cross multiply
    72.99x = 109.29 × 66.60
  4. Step 4: Simplify right side
    72.99x = 7,278.71
  5. Step 5: Solve for x
    x = 7,278.71/72.99
  6. Step 6: Final answer
    x = 99.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.