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Finding the Fourth Proportional to 72.60, 100.80 and 70.80

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Solution

The fourth proportional to 72.60, 100.80 and 70.80 is: 98.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.60 : 100.80 = 70.80 : x
  2. Step 2: Convert to fraction form
    72.60/100.80 = 70.80/x
  3. Step 3: Cross multiply
    72.60x = 100.80 × 70.80
  4. Step 4: Simplify right side
    72.60x = 7,136.64
  5. Step 5: Solve for x
    x = 7,136.64/72.60
  6. Step 6: Final answer
    x = 98.30

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.