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Finding the Fourth Proportional to 55.70, 76.86 and 31.15

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Solution

The fourth proportional to 55.70, 76.86 and 31.15 is: 42.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.70 : 76.86 = 31.15 : x
  2. Step 2: Convert to fraction form
    55.70/76.86 = 31.15/x
  3. Step 3: Cross multiply
    55.70x = 76.86 × 31.15
  4. Step 4: Simplify right side
    55.70x = 2,393.80
  5. Step 5: Solve for x
    x = 2,393.80/55.70
  6. Step 6: Final answer
    x = 42.98

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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.