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Finding the Fourth Proportional to 786.90, 1,085.90 and 455.28

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Solution

The fourth proportional to 786.90, 1,085.90 and 455.28 is: 628.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.90 : 1,085.90 = 455.28 : x
  2. Step 2: Convert to fraction form
    786.90/1,085.90 = 455.28/x
  3. Step 3: Cross multiply
    786.90x = 1,085.90 × 455.28
  4. Step 4: Simplify right side
    786.90x = 494,386.28
  5. Step 5: Solve for x
    x = 494,386.28/786.90
  6. Step 6: Final answer
    x = 628.27

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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.