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Finding the Fourth Proportional to 716.18, 988.15 and 421.40

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Solution

The fourth proportional to 716.18, 988.15 and 421.40 is: 581.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    716.18 : 988.15 = 421.40 : x
  2. Step 2: Convert to fraction form
    716.18/988.15 = 421.40/x
  3. Step 3: Cross multiply
    716.18x = 988.15 × 421.40
  4. Step 4: Simplify right side
    716.18x = 416,400.42
  5. Step 5: Solve for x
    x = 416,400.42/716.18
  6. Step 6: Final answer
    x = 581.42

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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.