Home / 821-1,231.50-213

Finding the Fourth Proportional to 821, 1,231.50 and 213

Calculator

Solution

The fourth proportional to 821, 1,231.50 and 213 is: 319.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    821 : 1,231.50 = 213 : x
  2. Step 2: Convert to fraction form
    821/1,231.50 = 213/x
  3. Step 3: Cross multiply
    821x = 1,231.50 × 213
  4. Step 4: Simplify right side
    821x = 262,309.50
  5. Step 5: Solve for x
    x = 262,309.50/821
  6. Step 6: Final answer
    x = 319.50

Related Problems

Find fourth proportional to 410.50, 615.75 and 106.50
Half scale
Find fourth proportional to 1,642, 2,463 and 426
Double scale
Find fourth proportional to 822, 1,233 and 214
Similar ratio
Find fourth proportional to 1,231.50, 1,847.25 and 319.50
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.