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Finding the Fourth Proportional to 718.61, 991.62 and 438.90

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Solution

The fourth proportional to 718.61, 991.62 and 438.90 is: 605.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    718.61 : 991.62 = 438.90 : x
  2. Step 2: Convert to fraction form
    718.61/991.62 = 438.90/x
  3. Step 3: Cross multiply
    718.61x = 991.62 × 438.90
  4. Step 4: Simplify right side
    718.61x = 435,222.02
  5. Step 5: Solve for x
    x = 435,222.02/718.61
  6. Step 6: Final answer
    x = 605.65

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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.