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Finding the Fourth Proportional to 1,389.90, 2,085.67 and 513.01

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Solution

The fourth proportional to 1,389.90, 2,085.67 and 513.01 is: 769.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.90 : 2,085.67 = 513.01 : x
  2. Step 2: Convert to fraction form
    1,389.90/2,085.67 = 513.01/x
  3. Step 3: Cross multiply
    1,389.90x = 2,085.67 × 513.01
  4. Step 4: Simplify right side
    1,389.90x = 1,069,967.00
  5. Step 5: Solve for x
    x = 1,069,967.00/1,389.90
  6. Step 6: Final answer
    x = 769.82

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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.