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Finding the Fourth Proportional to 983.51, 1,475.18 and 428.20

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Solution

The fourth proportional to 983.51, 1,475.18 and 428.20 is: 642.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    983.51 : 1,475.18 = 428.20 : x
  2. Step 2: Convert to fraction form
    983.51/1,475.18 = 428.20/x
  3. Step 3: Cross multiply
    983.51x = 1,475.18 × 428.20
  4. Step 4: Simplify right side
    983.51x = 631,672.08
  5. Step 5: Solve for x
    x = 631,672.08/983.51
  6. Step 6: Final answer
    x = 642.27

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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.