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Finding the Fourth Proportional to 718.90, 991.99 and 439.20

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Solution

The fourth proportional to 718.90, 991.99 and 439.20 is: 606.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.90 : 991.99 = 439.20 : x
  2. Step 2: Convert to fraction form
    718.90/991.99 = 439.20/x
  3. Step 3: Cross multiply
    718.90x = 991.99 × 439.20
  4. Step 4: Simplify right side
    718.90x = 435,680.91
  5. Step 5: Solve for x
    x = 435,680.91/718.90
  6. Step 6: Final answer
    x = 606.04

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.