Moderate -0.8 This is a straightforward sine rule application requiring students to set up sin A/13 = sin 15°/10 and solve for A, then recognize the obtuse solution. It's simpler than average as it's a direct single-method question with clear given information, though the obtuse angle requirement adds minimal complexity.
1 The triangle ABC has an obtuse angle at A . The angle at B is \(15 ^ { \circ }\). The length of AC is 10 cm and the length of BC is 13 cm .
Calculate the size of the angle at A .
1 The triangle ABC has an obtuse angle at A . The angle at B is $15 ^ { \circ }$. The length of AC is 10 cm and the length of BC is 13 cm .
Calculate the size of the angle at A .
\hfill \mbox{\textit{OCR MEI AS Paper 1 2024 Q1 [2]}}