4MA0 Higher June 2015 Paper 3 Q8
8 Here is a right-angled triangle.
Diagram NOT accurately drawn
\(AC = 6.5\) cm.
\(BC = 6.3\) cm.
Angle \(ABC = 90^\circ\)
Calculate the length of \(AB\).
(3)
| Scheme | Marks |
|---|---|
| \((AB^2 =)\;6.5^2 - 6.3^2\) (= 2.56) | M1 |
| \((AB =)\sqrt{6.5^2 - 6.3^2}\) or \(\sqrt{\text{"}2.56\text{"}}\) | M1 dep |
| 1.6 | A1 |
| (3) |
Notes
Alternative method
M1 for finding a correct angle (\(A = 75.7\ldots\); \(C = 14.2\ldots\)) AND a correct trig statement with a correct angle eg. \(\sin 14.2 = \dfrac{AB}{6.5}\)
M1 for making AB the subject eg. \(AB = 6.5 \sin 14.2\)
NB: 1.6 as a rounded answer eg. from 1.594… gains A0