Mathematics 0580 · IGCSE · Non-right-angled triangles

Non-right-angled triangles — practice question

ABCD is a quadrilateral in which $AB = 10.4\,\text{cm}$ and $AD = 6.5\,\text{cm}$. Angle $DAB = 64^{\circ}$, angle $BDC = 26^{\circ}$ and angle $DBC = 42^{\circ}$.
(a)[3]

Show that $BD = 9.55\,\text{cm}$, when rounded to 2 decimal places.

(b(i))[1]

Show that $BCD = 112^{\circ}$.

(b(ii))[3]

Calculate the value of $CD$.

(c)[3]

Find the minimum distance from $D$ to $AB$.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Use the cosine rule: $\sqrt{10.4^2+6.5^2-2\times10.4\times6.5\cos64}$

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