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Finding the Fourth Proportional to 191.30, 286.90 and 87.15

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Solution

The fourth proportional to 191.30, 286.90 and 87.15 is: 130.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    191.30 : 286.90 = 87.15 : x
  2. Step 2: Convert to fraction form
    191.30/286.90 = 87.15/x
  3. Step 3: Cross multiply
    191.30x = 286.90 × 87.15
  4. Step 4: Simplify right side
    191.30x = 25,004.19
  5. Step 5: Solve for x
    x = 25,004.19/191.30
  6. Step 6: Final answer
    x = 130.71

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.