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Finding the Fourth Proportional to 1,290.51, 1,780.87 and 731.08

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Solution

The fourth proportional to 1,290.51, 1,780.87 and 731.08 is: 1,008.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,290.51 : 1,780.87 = 731.08 : x
  2. Step 2: Convert to fraction form
    1,290.51/1,780.87 = 731.08/x
  3. Step 3: Cross multiply
    1,290.51x = 1,780.87 × 731.08
  4. Step 4: Simplify right side
    1,290.51x = 1,301,958.44
  5. Step 5: Solve for x
    x = 1,301,958.44/1,290.51
  6. Step 6: Final answer
    x = 1,008.87

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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.