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Finding the Fourth Proportional to 66.57, 91.74 and 65.40

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Solution

The fourth proportional to 66.57, 91.74 and 65.40 is: 90.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.57 : 91.74 = 65.40 : x
  2. Step 2: Convert to fraction form
    66.57/91.74 = 65.40/x
  3. Step 3: Cross multiply
    66.57x = 91.74 × 65.40
  4. Step 4: Simplify right side
    66.57x = 5,999.80
  5. Step 5: Solve for x
    x = 5,999.80/66.57
  6. Step 6: Final answer
    x = 90.13

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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.