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Finding the Fourth Proportional to 66.42, 91.68 and 51.90

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Solution

The fourth proportional to 66.42, 91.68 and 51.90 is: 71.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.42 : 91.68 = 51.90 : x
  2. Step 2: Convert to fraction form
    66.42/91.68 = 51.90/x
  3. Step 3: Cross multiply
    66.42x = 91.68 × 51.90
  4. Step 4: Simplify right side
    66.42x = 4,758.19
  5. Step 5: Solve for x
    x = 4,758.19/66.42
  6. Step 6: Final answer
    x = 71.64

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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.