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Finding the Fourth Proportional to 86.90, 119.70 and 70.47

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Solution

The fourth proportional to 86.90, 119.70 and 70.47 is: 97.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.90 : 119.70 = 70.47 : x
  2. Step 2: Convert to fraction form
    86.90/119.70 = 70.47/x
  3. Step 3: Cross multiply
    86.90x = 119.70 × 70.47
  4. Step 4: Simplify right side
    86.90x = 8,435.26
  5. Step 5: Solve for x
    x = 8,435.26/86.90
  6. Step 6: Final answer
    x = 97.07

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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.