Home / 821-1,231.68-308

Finding the Fourth Proportional to 821, 1,231.68 and 308

Calculator

Solution

The fourth proportional to 821, 1,231.68 and 308 is: 462.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    821 : 1,231.68 = 308 : x
  2. Step 2: Convert to fraction form
    821/1,231.68 = 308/x
  3. Step 3: Cross multiply
    821x = 1,231.68 × 308
  4. Step 4: Simplify right side
    821x = 379,357.44
  5. Step 5: Solve for x
    x = 379,357.44/821
  6. Step 6: Final answer
    x = 462.07

Related Problems

Find fourth proportional to 410.50, 615.84 and 154
Half scale
Find fourth proportional to 1,642, 2,463.36 and 616
Double scale
Find fourth proportional to 822, 1,233.18 and 309
Similar ratio
Find fourth proportional to 1,231.50, 1,847.52 and 462
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.