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Finding the Fourth Proportional to 915.21, 1,373.63 and 428.54

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Solution

The fourth proportional to 915.21, 1,373.63 and 428.54 is: 643.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    915.21 : 1,373.63 = 428.54 : x
  2. Step 2: Convert to fraction form
    915.21/1,373.63 = 428.54/x
  3. Step 3: Cross multiply
    915.21x = 1,373.63 × 428.54
  4. Step 4: Simplify right side
    915.21x = 588,655.40
  5. Step 5: Solve for x
    x = 588,655.40/915.21
  6. Step 6: Final answer
    x = 643.19

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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.