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Finding the Fourth Proportional to 1,370.69, 1,891.55 and 781.35

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Solution

The fourth proportional to 1,370.69, 1,891.55 and 781.35 is: 1,078.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,370.69 : 1,891.55 = 781.35 : x
  2. Step 2: Convert to fraction form
    1,370.69/1,891.55 = 781.35/x
  3. Step 3: Cross multiply
    1,370.69x = 1,891.55 × 781.35
  4. Step 4: Simplify right side
    1,370.69x = 1,477,957.45
  5. Step 5: Solve for x
    x = 1,477,957.45/1,370.69
  6. Step 6: Final answer
    x = 1,078.26

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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.