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Finding the Fourth Proportional to 865.32, 1,298.43 and 661.20

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Solution

The fourth proportional to 865.32, 1,298.43 and 661.20 is: 992.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.32 : 1,298.43 = 661.20 : x
  2. Step 2: Convert to fraction form
    865.32/1,298.43 = 661.20/x
  3. Step 3: Cross multiply
    865.32x = 1,298.43 × 661.20
  4. Step 4: Simplify right side
    865.32x = 858,521.92
  5. Step 5: Solve for x
    x = 858,521.92/865.32
  6. Step 6: Final answer
    x = 992.14

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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.