Home / 860.80-1,291.20-628.60

Finding the Fourth Proportional to 860.80, 1,291.20 and 628.60

Calculator

Solution

The fourth proportional to 860.80, 1,291.20 and 628.60 is: 942.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.80 : 1,291.20 = 628.60 : x
  2. Step 2: Convert to fraction form
    860.80/1,291.20 = 628.60/x
  3. Step 3: Cross multiply
    860.80x = 1,291.20 × 628.60
  4. Step 4: Simplify right side
    860.80x = 811,648.32
  5. Step 5: Solve for x
    x = 811,648.32/860.80
  6. Step 6: Final answer
    x = 942.90

Related Problems

Find fourth proportional to 430.40, 645.60 and 314.30
Half scale
Find fourth proportional to 1,721.60, 2,582.40 and 1,257.20
Double scale
Find fourth proportional to 861.80, 1,292.70 and 629.60
Similar ratio
Find fourth proportional to 1,291.20, 1,936.80 and 942.90
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.