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Finding the Fourth Proportional to 1,287.55, 1,776.86 and 728.08

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Solution

The fourth proportional to 1,287.55, 1,776.86 and 728.08 is: 1,004.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.55 : 1,776.86 = 728.08 : x
  2. Step 2: Convert to fraction form
    1,287.55/1,776.86 = 728.08/x
  3. Step 3: Cross multiply
    1,287.55x = 1,776.86 × 728.08
  4. Step 4: Simplify right side
    1,287.55x = 1,293,690.43
  5. Step 5: Solve for x
    x = 1,293,690.43/1,287.55
  6. Step 6: Final answer
    x = 1,004.77

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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.