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Finding the Fourth Proportional to 123.89, 170.87 and 87.06

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Solution

The fourth proportional to 123.89, 170.87 and 87.06 is: 120.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.89 : 170.87 = 87.06 : x
  2. Step 2: Convert to fraction form
    123.89/170.87 = 87.06/x
  3. Step 3: Cross multiply
    123.89x = 170.87 × 87.06
  4. Step 4: Simplify right side
    123.89x = 14,875.51
  5. Step 5: Solve for x
    x = 14,875.51/123.89
  6. Step 6: Final answer
    x = 120.08

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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.