MHB What is the perimeter of triangle ABC?

mathdad
Messages
1,280
Reaction score
0
The vertices of triangle ABC are A(1, 1), B(9, 3), and
C(3, 5).

1. Find the perimeter of triangle ABC.

I must use the distance formula for points on the xy-plane to find all three sides. I then add all three sides. Correct?

2. Find the perimeter of the triangle that is formed by joining the midpoints of the three sides of triangle ABC.

I am not too sure about part 2.

3. Compute the ratio of the perimeter in part 1 to the perimeter in part 2.

I will let R = ratio.

The set up for part 3 is

R = (perimeter of part 1)/(perimeter of part 2)

Correct? I cannot do part 3 without computing part 2, which I don't know how to do.
 
Mathematics news on Phys.org
RTCNTC said:
The vertices of triangle ABC are A(1, 1), B(9, 3), and
C(3, 5).

1. Find the perimeter of triangle ABC.

I must use the distance formula for points on the xy-plane to find all three sides. I then add all three sides. Correct?

Correct.

RTCNTC said:
2. Find the perimeter of the triangle that is formed by joining the midpoints of the three sides of triangle ABC.

A sheet of graph paper will be handy for this exercise. Mathematically, the coordinates of a midpoint may be found with

$$x_M=\frac{x_1+x_2}{2},\quad y_M=\frac{y_1+y_2}{2}$$

RTCNTC said:
3. Compute the ratio of the perimeter in part 1 to the perimeter in part 2.

I will let R = ratio.

The set up for part 3 is

R = (perimeter of part 1)/(perimeter of part 2)

Correct?

Correct. You may also write

$$P_1:P_2$$

As a hint, the desired ratio is 2:1.
 
1. Use the distance formula to find the distance between all 3 sides. Add all three sides. Adding all three sides yields perimeter 1.

2. Use the midpoint formula to find the midpoint of the distance between the three given points.

3. Find the distance between the 3 midpoints found in part 2 above. Add all 3 sides. This yields perimeter 2.

4. The ratio = (perimeter 1)/(perimeter 2)

This exercise is related more to geometry mixed with algebra. Correct? I did not post in the geometry forum because the question is from David Cohen's precalculus textbook.
 
Last edited:
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
I'm interested to know whether the equation $$1 = 2 - \frac{1}{2 - \frac{1}{2 - \cdots}}$$ is true or not. It can be shown easily that if the continued fraction converges, it cannot converge to anything else than 1. It seems that if the continued fraction converges, the convergence is very slow. The apparent slowness of the convergence makes it difficult to estimate the presence of true convergence numerically. At the moment I don't know whether this converges or not.

Similar threads

Replies
13
Views
4K
Replies
2
Views
2K
Replies
1
Views
933
Replies
2
Views
1K
Replies
1
Views
1K
Replies
5
Views
2K
Back
Top