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Finding the Fourth Proportional to 987.34, 1,487.67 and 817.78

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Solution

The fourth proportional to 987.34, 1,487.67 and 817.78 is: 1,232.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.34 : 1,487.67 = 817.78 : x
  2. Step 2: Convert to fraction form
    987.34/1,487.67 = 817.78/x
  3. Step 3: Cross multiply
    987.34x = 1,487.67 × 817.78
  4. Step 4: Simplify right side
    987.34x = 1,216,586.77
  5. Step 5: Solve for x
    x = 1,216,586.77/987.34
  6. Step 6: Final answer
    x = 1,232.19

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.