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Finding the Fourth Proportional to 64.85, 89.64 and 60.80

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Solution

The fourth proportional to 64.85, 89.64 and 60.80 is: 84.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    64.85 : 89.64 = 60.80 : x
  2. Step 2: Convert to fraction form
    64.85/89.64 = 60.80/x
  3. Step 3: Cross multiply
    64.85x = 89.64 × 60.80
  4. Step 4: Simplify right side
    64.85x = 5,449.66
  5. Step 5: Solve for x
    x = 5,449.66/64.85
  6. Step 6: Final answer
    x = 84.04

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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.