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Finding the Fourth Proportional to 84.99, 117.30 and 61.78

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Solution

The fourth proportional to 84.99, 117.30 and 61.78 is: 85.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.99 : 117.30 = 61.78 : x
  2. Step 2: Convert to fraction form
    84.99/117.30 = 61.78/x
  3. Step 3: Cross multiply
    84.99x = 117.30 × 61.78
  4. Step 4: Simplify right side
    84.99x = 7,246.79
  5. Step 5: Solve for x
    x = 7,246.79/84.99
  6. Step 6: Final answer
    x = 85.27

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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.