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Finding the Fourth Proportional to 1,140.20, 1,573.42 and 642.88

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Solution

The fourth proportional to 1,140.20, 1,573.42 and 642.88 is: 887.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,140.20 : 1,573.42 = 642.88 : x
  2. Step 2: Convert to fraction form
    1,140.20/1,573.42 = 642.88/x
  3. Step 3: Cross multiply
    1,140.20x = 1,573.42 × 642.88
  4. Step 4: Simplify right side
    1,140.20x = 1,011,520.25
  5. Step 5: Solve for x
    x = 1,011,520.25/1,140.20
  6. Step 6: Final answer
    x = 887.14

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1.5x scale

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.