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Finding the Fourth Proportional to 66.40, 91.29 and 56.68

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Solution

The fourth proportional to 66.40, 91.29 and 56.68 is: 77.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.40 : 91.29 = 56.68 : x
  2. Step 2: Convert to fraction form
    66.40/91.29 = 56.68/x
  3. Step 3: Cross multiply
    66.40x = 91.29 × 56.68
  4. Step 4: Simplify right side
    66.40x = 5,174.32
  5. Step 5: Solve for x
    x = 5,174.32/66.40
  6. Step 6: Final answer
    x = 77.93

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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.