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Finding the Fourth Proportional to 78.45, 116.99 and 71.62

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Solution

The fourth proportional to 78.45, 116.99 and 71.62 is: 106.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.45 : 116.99 = 71.62 : x
  2. Step 2: Convert to fraction form
    78.45/116.99 = 71.62/x
  3. Step 3: Cross multiply
    78.45x = 116.99 × 71.62
  4. Step 4: Simplify right side
    78.45x = 8,378.82
  5. Step 5: Solve for x
    x = 8,378.82/78.45
  6. Step 6: Final answer
    x = 106.80

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.