Lesson Example Discussion Quiz: Class Homework |
Step-3 |
Title: |
Grade: 10-a Lesson: S2-L6 |
Explanation: |
Steps | Statment | Solution |
---|---|---|
1 |
\begin{align} \text{Given} \\ \end{align} |
\begin{align} & \text{ABCD is a square,} AC \bot DB \\ & \text{AE = 2x - 6, EC = -3y + 10, DE = 5x and EB = 4y - 6} \\ \end{align} |
2 |
Consider \$\triangle AEB\$ and \$\triangle CED\$ |
\begin{align} AE &= CE \\ \angle AEB &= \angle CED \\ \angle EAB &= \angle ECD \\ ∴ \triangle AEB &\cong \triangle CED \\ \end{align} |
3 |
From \$\triangle AEB\$ and \$triangle CED\$ |
\begin{align} AE &= CE \\ EB &= ED \\ \end{align} |
4 |
\begin{align} \text{Consider AE = CE} \\ \end{align} |
\begin{align} && AE &= CE \\ \Rightarrow && 2x - 6 &= -3y + 10 \\ \Rightarrow && 2x + 3y &= 16 \tag{1} \label{1} \\ \end{align} |
5 |
\begin{align} \text{Consider EB = ED} \\ \end{align} |
\begin{align} && EB &= ED \\ \Rightarrow && 5x &= 4y - 6 \\ \Rightarrow && 5x - 4y &= - 6 \tag{2} \label{2} \\ \end{align} |
6 |
\begin{align} \text{Solving $(1)$ and $(2)$} \\ \end{align} |
\begin{align} 2x + 3y &= 16 \\ 5x - 4y &= -6 \\ \hline \end{align} |
7 |
\begin{align} \text{Multiply $(1)$ with 5 and $(2)$ with 2} \end{align} |
\begin{align}
10x + 15y &= 80 \\
10x - 8y &= -12 \\
\hline
\end{align} |
8 |
\begin{align} \text{Subtract $(2)$ from $(1)$} \\ \end{align} |
\begin{align} 10x + 15y &= 80 \\ - 10x + 8y &= 12 \\ \hline 23y &= 92 \\ y &= 4 \end{align} |
9 |
\begin{align} \text{Substitute y = 4 in $(1)$ } \end{align} |
\begin{align} && 2x + 3y &= 16 \\ \Rightarrow && 2x + 3(4) &= 16 \\ \Rightarrow && 2x + 12 &= 16 \\ \Rightarrow && 2x &= 16 - 12 \\ \Rightarrow && 2x &= 4 \\ \Rightarrow && x &= 2 \end{align} |
Given,
ABCD is a square, AC and DB are diagonals of the square and AC is perpendicular to DB.
Also sides AE = 2x - 6, EC = -3y + 10, DE = 5x and EB = 4y - 6.
In a square the diagoanls are bisect each other perpendicularly and equally.
\$∴\$ AE = EC = DE = EB.
Consider △AEB and △CED
\begin{align} AE &= CE \\ \angle AEB &= \angle CED \\ \angle EAB &= \angle ECD \\ ∴ \triangle AEB &\cong \triangle CED \\ \end{align}
From △AEB and △CED
\begin{align}
AE &= CE \\
EB &= ED \\
\end{align}
Since AE = CE
\begin{align} && AE &= CE \\ \Rightarrow && 2x - 6 &= -3y + 10 \\ \Rightarrow && 2x + 3y &= 16 \tag{1} \\ \end{align}
Since EB = ED
\begin{align} && EB &= ED \\ \Rightarrow && 5x &= 4y - 6 \\ \Rightarrow && 5x - 4y &= - 6 \tag{2} \\ \end{align}
Solving (1) and (2) for x and y:
\begin{align} 2x + 3y &= 16 \\ 5x - 4y &= -6 \\ \hline \end{align}
Multiply (1) with 5 and (2) with 2 \begin{align} 10x + 15y &= 80 \\ 10x - 8y &= -12 \\ \hline \end{align}
Now subtract (2) from (1) \begin{align} 10x + 15y &= 80 \\ - 10x + 8y &= 12 \\ \hline 23y &= 92 \\ \end{align}
\begin{align} 23y &= 92 \\ y &= 4 \end{align}
Substitute the value of y = 4 in (1) \begin{align} && 2x + 3y &= 16 \\ \Rightarrow && 2x + 3(4) &= 16 \\ \Rightarrow && 2x + 12 &= 16 \\ \Rightarrow && 2x &= 16 - 12 \\ \Rightarrow && 2x &= 4 \\ \Rightarrow && x &= 2 \end{align}
\begin{align} \therefore \text{x = 2 and y = 4} \end{align}
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