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Finding the Fourth Proportional to 66.48, 91.68 and 57.28

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Solution

The fourth proportional to 66.48, 91.68 and 57.28 is: 78.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.48 : 91.68 = 57.28 : x
  2. Step 2: Convert to fraction form
    66.48/91.68 = 57.28/x
  3. Step 3: Cross multiply
    66.48x = 91.68 × 57.28
  4. Step 4: Simplify right side
    66.48x = 5,251.43
  5. Step 5: Solve for x
    x = 5,251.43/66.48
  6. Step 6: Final answer
    x = 78.99

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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.