Home / 818.12-1,217.40-815.40

Finding the Fourth Proportional to 818.12, 1,217.40 and 815.40

Calculator

Solution

The fourth proportional to 818.12, 1,217.40 and 815.40 is: 1,213.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    818.12 : 1,217.40 = 815.40 : x
  2. Step 2: Convert to fraction form
    818.12/1,217.40 = 815.40/x
  3. Step 3: Cross multiply
    818.12x = 1,217.40 × 815.40
  4. Step 4: Simplify right side
    818.12x = 992,667.96
  5. Step 5: Solve for x
    x = 992,667.96/818.12
  6. Step 6: Final answer
    x = 1,213.35

Related Problems

Find fourth proportional to 409.06, 608.70 and 407.70
Half scale
Find fourth proportional to 1,636.24, 2,434.80 and 1,630.80
Double scale
Find fourth proportional to 819.12, 1,218.89 and 816.40
Similar ratio
Find fourth proportional to 1,227.18, 1,826.10 and 1,223.10
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.