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Finding the Fourth Proportional to 66.60, 91.26 and 66.15

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Solution

The fourth proportional to 66.60, 91.26 and 66.15 is: 90.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.60 : 91.26 = 66.15 : x
  2. Step 2: Convert to fraction form
    66.60/91.26 = 66.15/x
  3. Step 3: Cross multiply
    66.60x = 91.26 × 66.15
  4. Step 4: Simplify right side
    66.60x = 6,036.85
  5. Step 5: Solve for x
    x = 6,036.85/66.60
  6. Step 6: Final answer
    x = 90.64

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.