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Finding the Fourth Proportional to 1,247.60, 1,721.76 and 688.12

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Solution

The fourth proportional to 1,247.60, 1,721.76 and 688.12 is: 949.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,247.60 : 1,721.76 = 688.12 : x
  2. Step 2: Convert to fraction form
    1,247.60/1,721.76 = 688.12/x
  3. Step 3: Cross multiply
    1,247.60x = 1,721.76 × 688.12
  4. Step 4: Simplify right side
    1,247.60x = 1,184,777.49
  5. Step 5: Solve for x
    x = 1,184,777.49/1,247.60
  6. Step 6: Final answer
    x = 949.65

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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.