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Finding the Fourth Proportional to 786.15, 1,085.07 and 491.64

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Solution

The fourth proportional to 786.15, 1,085.07 and 491.64 is: 678.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    786.15 : 1,085.07 = 491.64 : x
  2. Step 2: Convert to fraction form
    786.15/1,085.07 = 491.64/x
  3. Step 3: Cross multiply
    786.15x = 1,085.07 × 491.64
  4. Step 4: Simplify right side
    786.15x = 533,463.81
  5. Step 5: Solve for x
    x = 533,463.81/786.15
  6. Step 6: Final answer
    x = 678.58

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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.