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Finding the Fourth Proportional to 65.40, 90.36 and 63.78

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Solution

The fourth proportional to 65.40, 90.36 and 63.78 is: 88.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.40 : 90.36 = 63.78 : x
  2. Step 2: Convert to fraction form
    65.40/90.36 = 63.78/x
  3. Step 3: Cross multiply
    65.40x = 90.36 × 63.78
  4. Step 4: Simplify right side
    65.40x = 5,763.16
  5. Step 5: Solve for x
    x = 5,763.16/65.40
  6. Step 6: Final answer
    x = 88.12

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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.