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Finding the Fourth Proportional to 65.78, 98.63 and 31.55

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Solution

The fourth proportional to 65.78, 98.63 and 31.55 is: 47.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.78 : 98.63 = 31.55 : x
  2. Step 2: Convert to fraction form
    65.78/98.63 = 31.55/x
  3. Step 3: Cross multiply
    65.78x = 98.63 × 31.55
  4. Step 4: Simplify right side
    65.78x = 3,111.13
  5. Step 5: Solve for x
    x = 3,111.13/65.78
  6. Step 6: Final answer
    x = 47.30

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.