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Finding the Fourth Proportional to 85.80, 118.40 and 56.66

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Solution

The fourth proportional to 85.80, 118.40 and 56.66 is: 78.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.80 : 118.40 = 56.66 : x
  2. Step 2: Convert to fraction form
    85.80/118.40 = 56.66/x
  3. Step 3: Cross multiply
    85.80x = 118.40 × 56.66
  4. Step 4: Simplify right side
    85.80x = 6,708.54
  5. Step 5: Solve for x
    x = 6,708.54/85.80
  6. Step 6: Final answer
    x = 78.19

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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.