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Finding the Fourth Proportional to 743.40, 1,109.64 and 690

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Solution

The fourth proportional to 743.40, 1,109.64 and 690 is: 1,029.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    743.40 : 1,109.64 = 690 : x
  2. Step 2: Convert to fraction form
    743.40/1,109.64 = 690/x
  3. Step 3: Cross multiply
    743.40x = 1,109.64 × 690
  4. Step 4: Simplify right side
    743.40x = 765,651.60
  5. Step 5: Solve for x
    x = 765,651.60/743.40
  6. Step 6: Final answer
    x = 1,029.93

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.