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Finding the Fourth Proportional to 1,221.30, 1,831.59 and 978.30

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Solution

The fourth proportional to 1,221.30, 1,831.59 and 978.30 is: 1,467.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.30 : 1,831.59 = 978.30 : x
  2. Step 2: Convert to fraction form
    1,221.30/1,831.59 = 978.30/x
  3. Step 3: Cross multiply
    1,221.30x = 1,831.59 × 978.30
  4. Step 4: Simplify right side
    1,221.30x = 1,791,844.50
  5. Step 5: Solve for x
    x = 1,791,844.50/1,221.30
  6. Step 6: Final answer
    x = 1,467.16

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.