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Finding the Fourth Proportional to 1,292.21, 1,938.45 and 642.77

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Solution

The fourth proportional to 1,292.21, 1,938.45 and 642.77 is: 964.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,292.21 : 1,938.45 = 642.77 : x
  2. Step 2: Convert to fraction form
    1,292.21/1,938.45 = 642.77/x
  3. Step 3: Cross multiply
    1,292.21x = 1,938.45 × 642.77
  4. Step 4: Simplify right side
    1,292.21x = 1,245,977.51
  5. Step 5: Solve for x
    x = 1,245,977.51/1,292.21
  6. Step 6: Final answer
    x = 964.22

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1.5x scale

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.