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Finding the Fourth Proportional to 65.85, 90.66 and 57.07

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Solution

The fourth proportional to 65.85, 90.66 and 57.07 is: 78.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.85 : 90.66 = 57.07 : x
  2. Step 2: Convert to fraction form
    65.85/90.66 = 57.07/x
  3. Step 3: Cross multiply
    65.85x = 90.66 × 57.07
  4. Step 4: Simplify right side
    65.85x = 5,173.97
  5. Step 5: Solve for x
    x = 5,173.97/65.85
  6. Step 6: Final answer
    x = 78.57

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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.