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Finding the Fourth Proportional to 1,248.40, 1,722.78 and 688.88

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Solution

The fourth proportional to 1,248.40, 1,722.78 and 688.88 is: 950.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,248.40 : 1,722.78 = 688.88 : x
  2. Step 2: Convert to fraction form
    1,248.40/1,722.78 = 688.88/x
  3. Step 3: Cross multiply
    1,248.40x = 1,722.78 × 688.88
  4. Step 4: Simplify right side
    1,248.40x = 1,186,784.81
  5. Step 5: Solve for x
    x = 1,186,784.81/1,248.40
  6. Step 6: Final answer
    x = 950.64

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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.