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Finding the Fourth Proportional to 948.45, 1,421.91 and 428.19

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Solution

The fourth proportional to 948.45, 1,421.91 and 428.19 is: 641.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    948.45 : 1,421.91 = 428.19 : x
  2. Step 2: Convert to fraction form
    948.45/1,421.91 = 428.19/x
  3. Step 3: Cross multiply
    948.45x = 1,421.91 × 428.19
  4. Step 4: Simplify right side
    948.45x = 608,847.64
  5. Step 5: Solve for x
    x = 608,847.64/948.45
  6. Step 6: Final answer
    x = 641.94

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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.