Mathematics 4024 · O Level · Right-angled triangles
Right-angled triangles — practice question
In the figure labelled $ABCDEF$, $BCD$ lies on one straight line, and $CA$ is parallel to $DF$. The angles $\angle ABD$, $\angle BDE$ and $\angle DEF$ are all right angles. Also, $AB = 4\text{ m}$, $DE = 11\text{ m}$ and $EF = 4\text{ m}$.
(a)[2]
Given that $\angle FDE = x^\circ$, Show that $x = 20.0$ correct to $3$ significant figures.
(b)[1]
Since $\angle BAC = y^\circ$, Stating your reasons, explain why $y = x$.
(c)[3]
Calculate $AC$.
(d)[4]
The perpendicular separation between the parallel lines $CA$ and $DF$ is $7\text{ m}$. Calculate the area of $ACDF$.
Worked solution & mark scheme
This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Therefore, $\tan x=\frac{4}{11}$” …