4MA0 Foundation June 2015 Paper 1 Q22
22 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 |
| 1.6 | A1 |
| (3) | |
| Total 3 marks |
Notes
M1: dep
A1: NB. 1.6 as a rounded answer eg. from 1.594… gains A0
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. \(AB = 6.5\sin 14.2\)