Home / 813.08-1,219.80-380

Finding the Fourth Proportional to 813.08, 1,219.80 and 380

Calculator

Solution

The fourth proportional to 813.08, 1,219.80 and 380 is: 570.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.08 : 1,219.80 = 380 : x
  2. Step 2: Convert to fraction form
    813.08/1,219.80 = 380/x
  3. Step 3: Cross multiply
    813.08x = 1,219.80 × 380
  4. Step 4: Simplify right side
    813.08x = 463,524
  5. Step 5: Solve for x
    x = 463,524/813.08
  6. Step 6: Final answer
    x = 570.08

Related Problems

Find fourth proportional to 406.54, 609.90 and 190
Half scale
Find fourth proportional to 1,626.16, 2,439.60 and 760
Double scale
Find fourth proportional to 814.08, 1,221.30 and 381
Similar ratio
Find fourth proportional to 1,219.62, 1,829.70 and 570
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.