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Finding the Fourth Proportional to 987.42, 1,480.98 and 621.09

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Solution

The fourth proportional to 987.42, 1,480.98 and 621.09 is: 931.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.42 : 1,480.98 = 621.09 : x
  2. Step 2: Convert to fraction form
    987.42/1,480.98 = 621.09/x
  3. Step 3: Cross multiply
    987.42x = 1,480.98 × 621.09
  4. Step 4: Simplify right side
    987.42x = 919,821.87
  5. Step 5: Solve for x
    x = 919,821.87/987.42
  6. Step 6: Final answer
    x = 931.54

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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.