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Finding the Fourth Proportional to 1,239.38, 1,710.42 and 715.45

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Solution

The fourth proportional to 1,239.38, 1,710.42 and 715.45 is: 987.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.38 : 1,710.42 = 715.45 : x
  2. Step 2: Convert to fraction form
    1,239.38/1,710.42 = 715.45/x
  3. Step 3: Cross multiply
    1,239.38x = 1,710.42 × 715.45
  4. Step 4: Simplify right side
    1,239.38x = 1,223,711.44
  5. Step 5: Solve for x
    x = 1,223,711.44/1,239.38
  6. Step 6: Final answer
    x = 987.36

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Half scale
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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.