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Finding the Fourth Proportional to 1,389.59, 2,085.08 and 648.89

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Solution

The fourth proportional to 1,389.59, 2,085.08 and 648.89 is: 973.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.59 : 2,085.08 = 648.89 : x
  2. Step 2: Convert to fraction form
    1,389.59/2,085.08 = 648.89/x
  3. Step 3: Cross multiply
    1,389.59x = 2,085.08 × 648.89
  4. Step 4: Simplify right side
    1,389.59x = 1,352,973.89
  5. Step 5: Solve for x
    x = 1,352,973.89/1,389.59
  6. Step 6: Final answer
    x = 973.65

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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.