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Finding the Fourth Proportional to 1,290.78, 1,928.76 and 876.45

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Solution

The fourth proportional to 1,290.78, 1,928.76 and 876.45 is: 1,309.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.78 : 1,928.76 = 876.45 : x
  2. Step 2: Convert to fraction form
    1,290.78/1,928.76 = 876.45/x
  3. Step 3: Cross multiply
    1,290.78x = 1,928.76 × 876.45
  4. Step 4: Simplify right side
    1,290.78x = 1,690,461.70
  5. Step 5: Solve for x
    x = 1,690,461.70/1,290.78
  6. Step 6: Final answer
    x = 1,309.64

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.