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Finding the Fourth Proportional to 1,279.65, 1,918.35 and 621.20

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Solution

The fourth proportional to 1,279.65, 1,918.35 and 621.20 is: 931.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.65 : 1,918.35 = 621.20 : x
  2. Step 2: Convert to fraction form
    1,279.65/1,918.35 = 621.20/x
  3. Step 3: Cross multiply
    1,279.65x = 1,918.35 × 621.20
  4. Step 4: Simplify right side
    1,279.65x = 1,191,669.43
  5. Step 5: Solve for x
    x = 1,191,669.43/1,279.65
  6. Step 6: Final answer
    x = 931.25

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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.