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Finding the Fourth Proportional to 981.21, 1,471.63 and 287.72

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Solution

The fourth proportional to 981.21, 1,471.63 and 287.72 is: 431.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    981.21 : 1,471.63 = 287.72 : x
  2. Step 2: Convert to fraction form
    981.21/1,471.63 = 287.72/x
  3. Step 3: Cross multiply
    981.21x = 1,471.63 × 287.72
  4. Step 4: Simplify right side
    981.21x = 423,417.38
  5. Step 5: Solve for x
    x = 423,417.38/981.21
  6. Step 6: Final answer
    x = 431.53

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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.