Home / 308-391

Finding the Third Proportional to 308 and 391

Calculator

Solution

The third proportional to 308 and 391 is: 496.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    308 : 391 = 391 : x
  2. Step 2: Convert to fraction form
    308/391 = 391/x
  3. Step 3: Cross multiply
    308x = 391 × 391
  4. Step 4: Simplify right side
    308x = 152,881
  5. Step 5: Solve for x
    x = 152,881/308
  6. Step 6: Final answer
    x = 496.37

Related Problems

Find third proportional to 154 and 195.50
Half scale
Find third proportional to 616 and 782
Double scale
Find third proportional to 310 and 394
Similar ratio
Find third proportional to 462 and 586.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.27) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.