## Solve Lesson 72 Page 97 SBT Math 10 – Kite>

Topic

In the coordinate plane Oxygenfor triangle ABC yes A(− 1 ; − 5), REMOVE(5 ; 2) and weight

center is the origin. Point coordinates OLD to be:

A. (4 ; -3) B. (-4 ; -3) C. (-4 ; 3) D. (4 ; 3)

Solution method – See details

Apply the result: If WOOD(a; b) is the centroid ofABC with $$A({x_A};{y_A}),B({x_B};{y_B}),C({x_C};{y_C})$$ then $$\left\{ \begin{array}{ l}a = \frac{{{x_A} + {x_B} + {x_C}}}{3}\\b = \frac{{{y_A} + {y_B} + {y_C}}}{3}\end {array} \right.$$ to find point coordinates OLD

Detailed explanation

According to the assumption, O is the focusABC so $$\left\{ \begin{array}{l}\frac{{ – 1 + 5 + {x_C}}}{3} = 0\\\frac{{ – 5 + 2 + {y_C}}} {3} = 0\end{array} \right.$$$$\Rightarrow \left\{ \begin{array}{l}{x_C} = – 4\\{y_C} = 3\end{array} \ right.$$

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