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Finding the Fourth Proportional to 1,242.75, 1,862.96 and 420.45

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Solution

The fourth proportional to 1,242.75, 1,862.96 and 420.45 is: 630.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,242.75 : 1,862.96 = 420.45 : x
  2. Step 2: Convert to fraction form
    1,242.75/1,862.96 = 420.45/x
  3. Step 3: Cross multiply
    1,242.75x = 1,862.96 × 420.45
  4. Step 4: Simplify right side
    1,242.75x = 783,280.64
  5. Step 5: Solve for x
    x = 783,280.64/1,242.75
  6. Step 6: Final answer
    x = 630.28

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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.