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Finding the Fourth Proportional to 743.08, 1,111.26 and 639.40

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Solution

The fourth proportional to 743.08, 1,111.26 and 639.40 is: 956.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    743.08 : 1,111.26 = 639.40 : x
  2. Step 2: Convert to fraction form
    743.08/1,111.26 = 639.40/x
  3. Step 3: Cross multiply
    743.08x = 1,111.26 × 639.40
  4. Step 4: Simplify right side
    743.08x = 710,539.64
  5. Step 5: Solve for x
    x = 710,539.64/743.08
  6. Step 6: Final answer
    x = 956.21

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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.