Home / 387-641

Finding the Third Proportional to 387 and 641

Calculator

Solution

The third proportional to 387 and 641 is: 1,061.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    387 : 641 = 641 : x
  2. Step 2: Convert to fraction form
    387/641 = 641/x
  3. Step 3: Cross multiply
    387x = 641 × 641
  4. Step 4: Simplify right side
    387x = 410,881
  5. Step 5: Solve for x
    x = 410,881/387
  6. Step 6: Final answer
    x = 1,061.71

Related Problems

Find third proportional to 193.50 and 320.50
Half scale
Find third proportional to 774 and 1,282
Double scale
Find third proportional to 389 and 644
Similar ratio
Find third proportional to 580.50 and 961.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.66) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.