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Finding the Fourth Proportional to 1,258.40, 1,888.72 and 642.53

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Solution

The fourth proportional to 1,258.40, 1,888.72 and 642.53 is: 964.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,258.40 : 1,888.72 = 642.53 : x
  2. Step 2: Convert to fraction form
    1,258.40/1,888.72 = 642.53/x
  3. Step 3: Cross multiply
    1,258.40x = 1,888.72 × 642.53
  4. Step 4: Simplify right side
    1,258.40x = 1,213,562.38
  5. Step 5: Solve for x
    x = 1,213,562.38/1,258.40
  6. Step 6: Final answer
    x = 964.37

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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.