Geometry guide chap 3 ques no 11 (pg66)

[apoorvaditya007]

In the solution to the problem on page number 71, (ques on page 66)
first the area of one triangle has been calculated to 18 and then the area of the bigger traingle is simply equated to that area. Why?
Nowhere there is mentioned that the areas are equal

[tommywallach]

Hey Apoor,

No, they're actually calculating the SAME triangle twice. Remember, every triangle has three bases and three heights (depending on how you turn the triangle). So once you know the area is 18, you can "turn" it, and solve for a different height (assuming you know a different base). Make sense?

-t