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Finding the Fourth Proportional to 84.80, 117.01 and 72.40

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Solution

The fourth proportional to 84.80, 117.01 and 72.40 is: 99.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    84.80 : 117.01 = 72.40 : x
  2. Step 2: Convert to fraction form
    84.80/117.01 = 72.40/x
  3. Step 3: Cross multiply
    84.80x = 117.01 × 72.40
  4. Step 4: Simplify right side
    84.80x = 8,471.73
  5. Step 5: Solve for x
    x = 8,471.73/84.80
  6. Step 6: Final answer
    x = 99.90

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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.