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Finding the Fourth Proportional to 708.21, 977.31 and 428.40

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Solution

The fourth proportional to 708.21, 977.31 and 428.40 is: 591.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.21 : 977.31 = 428.40 : x
  2. Step 2: Convert to fraction form
    708.21/977.31 = 428.40/x
  3. Step 3: Cross multiply
    708.21x = 977.31 × 428.40
  4. Step 4: Simplify right side
    708.21x = 418,679.60
  5. Step 5: Solve for x
    x = 418,679.60/708.21
  6. Step 6: Final answer
    x = 591.18

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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.