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Finding the Fourth Proportional to 987.34, 1,478.58 and 621.22

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Solution

The fourth proportional to 987.34, 1,478.58 and 621.22 is: 930.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    987.34 : 1,478.58 = 621.22 : x
  2. Step 2: Convert to fraction form
    987.34/1,478.58 = 621.22/x
  3. Step 3: Cross multiply
    987.34x = 1,478.58 × 621.22
  4. Step 4: Simplify right side
    987.34x = 918,523.47
  5. Step 5: Solve for x
    x = 918,523.47/987.34
  6. Step 6: Final answer
    x = 930.30

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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.