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Finding the Fourth Proportional to 100.58, 138.51 and 86.00

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Solution

The fourth proportional to 100.58, 138.51 and 86.00 is: 118.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.58 : 138.51 = 86.00 : x
  2. Step 2: Convert to fraction form
    100.58/138.51 = 86.00/x
  3. Step 3: Cross multiply
    100.58x = 138.51 × 86.00
  4. Step 4: Simplify right side
    100.58x = 11,911.17
  5. Step 5: Solve for x
    x = 11,911.17/100.58
  6. Step 6: Final answer
    x = 118.43

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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.