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Finding the Fourth Proportional to 914.80, 1,372.20 and 428.32

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Solution

The fourth proportional to 914.80, 1,372.20 and 428.32 is: 642.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    914.80 : 1,372.20 = 428.32 : x
  2. Step 2: Convert to fraction form
    914.80/1,372.20 = 428.32/x
  3. Step 3: Cross multiply
    914.80x = 1,372.20 × 428.32
  4. Step 4: Simplify right side
    914.80x = 587,740.70
  5. Step 5: Solve for x
    x = 587,740.70/914.80
  6. Step 6: Final answer
    x = 642.48

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Double scale
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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.