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Finding the Fourth Proportional to 1,281.40, 1,767.90 and 783.76

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Solution

The fourth proportional to 1,281.40, 1,767.90 and 783.76 is: 1,081.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,281.40 : 1,767.90 = 783.76 : x
  2. Step 2: Convert to fraction form
    1,281.40/1,767.90 = 783.76/x
  3. Step 3: Cross multiply
    1,281.40x = 1,767.90 × 783.76
  4. Step 4: Simplify right side
    1,281.40x = 1,385,609.30
  5. Step 5: Solve for x
    x = 1,385,609.30/1,281.40
  6. Step 6: Final answer
    x = 1,081.32

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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.