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Finding the Fourth Proportional to 646.16, 890.76 and 490.64

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Solution

The fourth proportional to 646.16, 890.76 and 490.64 is: 676.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    646.16 : 890.76 = 490.64 : x
  2. Step 2: Convert to fraction form
    646.16/890.76 = 490.64/x
  3. Step 3: Cross multiply
    646.16x = 890.76 × 490.64
  4. Step 4: Simplify right side
    646.16x = 437,042.49
  5. Step 5: Solve for x
    x = 437,042.49/646.16
  6. Step 6: Final answer
    x = 676.37

Related Problems

Find fourth proportional to 323.08, 445.38 and 245.32
Half scale
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Double scale
Find fourth proportional to 647.16, 892.14 and 491.64
Similar ratio
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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.