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Finding the Fourth Proportional to 1,287.81, 1,927.56 and 917.40

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Solution

The fourth proportional to 1,287.81, 1,927.56 and 917.40 is: 1,373.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.81 : 1,927.56 = 917.40 : x
  2. Step 2: Convert to fraction form
    1,287.81/1,927.56 = 917.40/x
  3. Step 3: Cross multiply
    1,287.81x = 1,927.56 × 917.40
  4. Step 4: Simplify right side
    1,287.81x = 1,768,343.54
  5. Step 5: Solve for x
    x = 1,768,343.54/1,287.81
  6. Step 6: Final answer
    x = 1,373.14

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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.