No i don't have lengths. It is supposed to apply to any trapezoid. Now i found this link Trapezoid -- from Wolfram MathWorld which gives formulas as to why the areas are equal. But i don't understand why.
Hello, Aquameatwad!
How do you prove the area of Triangle A is equal to Triangle B in this trapezoid?
Code:P Q - *-------* : * * * * : * A * * B * : * * * * h * * * * : * * C * * : * * * * : ** ** - *-------------------------------* S R
$\displaystyle \Delta PSR\text{ and }\Delta QSR\text{ have the same base (SR) and the same height (h).}$
$\displaystyle \text{Hence: }\:\text{area}(\Delta PSR) \;=\;\text{area}(\Delta QSR)$
. . . . . . . . . . $\displaystyle A + C \;=\;B + C$
$\displaystyle \text{Therefore: }\qquad\quad\; A \;=\;B$
Wow Soroban its that simple? I was trying to prove it by somehow by showing Triangle C was congruent to the Triangle with base PQ ( i guess we can call it D). which it is. Could i have used this information to prove A=B?