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Finding the Fourth Proportional to 1,542.40, 2,128.42 and 912.78

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Solution

The fourth proportional to 1,542.40, 2,128.42 and 912.78 is: 1,259.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,542.40 : 2,128.42 = 912.78 : x
  2. Step 2: Convert to fraction form
    1,542.40/2,128.42 = 912.78/x
  3. Step 3: Cross multiply
    1,542.40x = 2,128.42 × 912.78
  4. Step 4: Simplify right side
    1,542.40x = 1,942,779.21
  5. Step 5: Solve for x
    x = 1,942,779.21/1,542.40
  6. Step 6: Final answer
    x = 1,259.58

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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.