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Finding the Fourth Proportional to 1,290.53, 1,780.98 and 723.40

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Solution

The fourth proportional to 1,290.53, 1,780.98 and 723.40 is: 998.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.53 : 1,780.98 = 723.40 : x
  2. Step 2: Convert to fraction form
    1,290.53/1,780.98 = 723.40/x
  3. Step 3: Cross multiply
    1,290.53x = 1,780.98 × 723.40
  4. Step 4: Simplify right side
    1,290.53x = 1,288,360.93
  5. Step 5: Solve for x
    x = 1,288,360.93/1,290.53
  6. Step 6: Final answer
    x = 998.32

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.