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Finding the Fourth Proportional to 1,275.30, 1,759.70 and 715.80

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Solution

The fourth proportional to 1,275.30, 1,759.70 and 715.80 is: 987.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,275.30 : 1,759.70 = 715.80 : x
  2. Step 2: Convert to fraction form
    1,275.30/1,759.70 = 715.80/x
  3. Step 3: Cross multiply
    1,275.30x = 1,759.70 × 715.80
  4. Step 4: Simplify right side
    1,275.30x = 1,259,593.26
  5. Step 5: Solve for x
    x = 1,259,593.26/1,275.30
  6. Step 6: Final answer
    x = 987.68

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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.