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Finding the Fourth Proportional to 891.32, 1,336.98 and 428.90

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Solution

The fourth proportional to 891.32, 1,336.98 and 428.90 is: 643.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    891.32 : 1,336.98 = 428.90 : x
  2. Step 2: Convert to fraction form
    891.32/1,336.98 = 428.90/x
  3. Step 3: Cross multiply
    891.32x = 1,336.98 × 428.90
  4. Step 4: Simplify right side
    891.32x = 573,430.72
  5. Step 5: Solve for x
    x = 573,430.72/891.32
  6. Step 6: Final answer
    x = 643.35

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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.