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Finding the Fourth Proportional to 1,298.59, 1,947.90 and 991

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Solution

The fourth proportional to 1,298.59, 1,947.90 and 991 is: 1,486.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,298.59 : 1,947.90 = 991 : x
  2. Step 2: Convert to fraction form
    1,298.59/1,947.90 = 991/x
  3. Step 3: Cross multiply
    1,298.59x = 1,947.90 × 991
  4. Step 4: Simplify right side
    1,298.59x = 1,930,368.90
  5. Step 5: Solve for x
    x = 1,930,368.90/1,298.59
  6. Step 6: Final answer
    x = 1,486.51

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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.