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Finding the Fourth Proportional to 1,388.93, 1,917.03 and 947

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Solution

The fourth proportional to 1,388.93, 1,917.03 and 947 is: 1,307.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,388.93 : 1,917.03 = 947 : x
  2. Step 2: Convert to fraction form
    1,388.93/1,917.03 = 947/x
  3. Step 3: Cross multiply
    1,388.93x = 1,917.03 × 947
  4. Step 4: Simplify right side
    1,388.93x = 1,815,427.41
  5. Step 5: Solve for x
    x = 1,815,427.41/1,388.93
  6. Step 6: Final answer
    x = 1,307.07

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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.