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Finding the Fourth Proportional to 85.68, 117.72 and 68.40

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Solution

The fourth proportional to 85.68, 117.72 and 68.40 is: 93.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.68 : 117.72 = 68.40 : x
  2. Step 2: Convert to fraction form
    85.68/117.72 = 68.40/x
  3. Step 3: Cross multiply
    85.68x = 117.72 × 68.40
  4. Step 4: Simplify right side
    85.68x = 8,052.05
  5. Step 5: Solve for x
    x = 8,052.05/85.68
  6. Step 6: Final answer
    x = 93.98

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.