Home / 860.31-1,290.45-211.05

Finding the Fourth Proportional to 860.31, 1,290.45 and 211.05

Calculator

Solution

The fourth proportional to 860.31, 1,290.45 and 211.05 is: 316.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.31 : 1,290.45 = 211.05 : x
  2. Step 2: Convert to fraction form
    860.31/1,290.45 = 211.05/x
  3. Step 3: Cross multiply
    860.31x = 1,290.45 × 211.05
  4. Step 4: Simplify right side
    860.31x = 272,349.47
  5. Step 5: Solve for x
    x = 272,349.47/860.31
  6. Step 6: Final answer
    x = 316.57

Related Problems

Find fourth proportional to 430.16, 645.23 and 105.53
Half scale
Find fourth proportional to 1,720.62, 2,580.90 and 422.10
Double scale
Find fourth proportional to 861.31, 1,291.95 and 212.05
Similar ratio
Find fourth proportional to 1,290.47, 1,935.68 and 316.58
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.