MHB What is the area of triangle $STV$?

  • Thread starter Thread starter anemone
  • Start date Start date
  • Tags Tags
    Area Triangle
AI Thread Summary
The problem involves finding the area of triangle STV given that the area of triangle XVU is 14 cm². It is established that the area of triangle UVT is three times that of triangle UVX due to equal heights and a base that is three times longer. Consequently, the area of triangle STV is calculated to be 42 cm². This conclusion is reached by applying geometric principles related to base and height in triangles. The solution highlights the relationships between the triangles based on their dimensions.
anemone
Gold Member
MHB
POTW Director
Messages
3,851
Reaction score
115
Hi all, I happened to see this primary 6 math geometry problem and thought it was a fun (not straightforward but not too hard) problem. Try it and post your solution if you are interested. (Cool)

In the figure, not drawn to scale, $UX=XY=YT$ and $UV=VS$. Given that the area of triangle $XVU$ is 14 cm$^2$, find the area of triangle $STV$.
[TIKZ]
\coordinate[label=left:U] (U) at (0,0);
\coordinate[label=right:T] (T) at (12, 0);
\coordinate[label=below: X] (X) at (4,0);
\coordinate[label=below: Y] (Y) at (8,0);
\coordinate[label=above: V] (V) at (2,1);
\coordinate[label=above:S] (S) at (4,2);
\coordinate[label=above: W] (W) at (7.2,0.4);
\draw (S) -- (U)-- (T)-- (S);
\draw (V) -- (X);
\draw (S) -- (Y);
\draw (V) -- (T);
[/TIKZ]
 
Mathematics news on Phys.org
Area of $\triangle STV$ = area of $\triangle UVT$

because they are on equal base and same base

now area of $\triangle UVT$ is 3 times area of $\triangle UVX$

as height is same and base is 3 times

so area of $\triangle STV$ = 3 * area of $\triangle UVX$ = $42cm^2$
 
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
Thread 'Unit Circle Double Angle Derivations'
Here I made a terrible mistake of assuming this to be an equilateral triangle and set 2sinx=1 => x=pi/6. Although this did derive the double angle formulas it also led into a terrible mess trying to find all the combinations of sides. I must have been tired and just assumed 6x=180 and 2sinx=1. By that time, I was so mindset that I nearly scolded a person for even saying 90-x. I wonder if this is a case of biased observation that seeks to dis credit me like Jesus of Nazareth since in reality...
Thread 'Imaginary Pythagoras'
I posted this in the Lame Math thread, but it's got me thinking. Is there any validity to this? Or is it really just a mathematical trick? Naively, I see that i2 + plus 12 does equal zero2. But does this have a meaning? I know one can treat the imaginary number line as just another axis like the reals, but does that mean this does represent a triangle in the complex plane with a hypotenuse of length zero? Ibix offered a rendering of the diagram using what I assume is matrix* notation...

Similar threads

Replies
2
Views
1K
Replies
2
Views
1K
Replies
9
Views
2K
Replies
1
Views
2K
Replies
6
Views
2K
Replies
7
Views
3K
Back
Top