Home / 804.60-1,206.90-419.80

Finding the Fourth Proportional to 804.60, 1,206.90 and 419.80

Calculator

Solution

The fourth proportional to 804.60, 1,206.90 and 419.80 is: 629.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    804.60 : 1,206.90 = 419.80 : x
  2. Step 2: Convert to fraction form
    804.60/1,206.90 = 419.80/x
  3. Step 3: Cross multiply
    804.60x = 1,206.90 × 419.80
  4. Step 4: Simplify right side
    804.60x = 506,656.62
  5. Step 5: Solve for x
    x = 506,656.62/804.60
  6. Step 6: Final answer
    x = 629.70

Related Problems

Find fourth proportional to 402.30, 603.45 and 209.90
Half scale
Find fourth proportional to 1,609.20, 2,413.80 and 839.60
Double scale
Find fourth proportional to 805.60, 1,208.40 and 420.80
Similar ratio
Find fourth proportional to 1,206.90, 1,810.35 and 629.70
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.