Question

PLEASE HELP THIS IS MY LAST QUESTION!

Triangle JKL is an equilateral triangle with two of its vertices at points J and K. What are the coordinates of point L? Round to the nearest tenth as needed.

Answer 1

(6, 7.2)

Explanation:

Since it is an equilateral triangle, all of the side length must be equal.

Therefore, we know the lengths JK = 6 and JL = 6. If h is the height of the triangle, the Pythagoras's theorem says

(JK/2)² + h² = JL²

putting in the values of JK and JL gives

(6/2)² + h² = 6²

3² + h² = 6²

subtracting 3^2 from both sides gives

h² = 6² - 3²

h² = 27

Taking the square root of both sides gives

h =

`\sqrt[3]{3}`

h = 5.2

With the value of h in hand, we can now read off the coordinates of L.

The x coordinates of L is 6 (count the boxes along the x-axis until you are under L or halfway between J and K).

The y-coordinates of L is 2 + h = 2 + 5.2 = 7.2 ( how far above the x-axis the triangle is plus the height of the triangle).

Answer 2

The X coordinate is 6, since it's midway between J and K. If you draw a midline from L, and running to the midpoint of the line JK, you make two right angled triangle. The length of the midline would be the square root of the difference of the squares of six and three, which is 5.20, which is the offset of the Y coordinate of L from the Y coordinate of J and K, which is 2. Add 5.20 to 2 to get the Y coordinate of L as 7.20. L is therefore (6,7.20)