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Finding the Fourth Proportional to 1,122.51, 1,683.99 and 429.20

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Solution

The fourth proportional to 1,122.51, 1,683.99 and 429.20 is: 643.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,122.51 : 1,683.99 = 429.20 : x
  2. Step 2: Convert to fraction form
    1,122.51/1,683.99 = 429.20/x
  3. Step 3: Cross multiply
    1,122.51x = 1,683.99 × 429.20
  4. Step 4: Simplify right side
    1,122.51x = 722,766.40
  5. Step 5: Solve for x
    x = 722,766.40/1,122.51
  6. Step 6: Final answer
    x = 643.89

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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.