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Finding the Fourth Proportional to 1,247.43, 1,721.45 and 687.89

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Solution

The fourth proportional to 1,247.43, 1,721.45 and 687.89 is: 949.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,247.43 : 1,721.45 = 687.89 : x
  2. Step 2: Convert to fraction form
    1,247.43/1,721.45 = 687.89/x
  3. Step 3: Cross multiply
    1,247.43x = 1,721.45 × 687.89
  4. Step 4: Simplify right side
    1,247.43x = 1,184,168.24
  5. Step 5: Solve for x
    x = 1,184,168.24/1,247.43
  6. Step 6: Final answer
    x = 949.29

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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.