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Finding the Fourth Proportional to 1,390.06, 1,919.86 and 947.19

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Solution

The fourth proportional to 1,390.06, 1,919.86 and 947.19 is: 1,308.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,390.06 : 1,919.86 = 947.19 : x
  2. Step 2: Convert to fraction form
    1,390.06/1,919.86 = 947.19/x
  3. Step 3: Cross multiply
    1,390.06x = 1,919.86 × 947.19
  4. Step 4: Simplify right side
    1,390.06x = 1,818,474.63
  5. Step 5: Solve for x
    x = 1,818,474.63/1,390.06
  6. Step 6: Final answer
    x = 1,308.20

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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.