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Finding the Fourth Proportional to 1,389.07, 1,916.90 and 768.07

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Solution

The fourth proportional to 1,389.07, 1,916.90 and 768.07 is: 1,059.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.07 : 1,916.90 = 768.07 : x
  2. Step 2: Convert to fraction form
    1,389.07/1,916.90 = 768.07/x
  3. Step 3: Cross multiply
    1,389.07x = 1,916.90 × 768.07
  4. Step 4: Simplify right side
    1,389.07x = 1,472,313.38
  5. Step 5: Solve for x
    x = 1,472,313.38/1,389.07
  6. Step 6: Final answer
    x = 1,059.93

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1.5x scale

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.