∠CAD = ∠BAC + ∠BAD
1) ∠CAD = 80° + 170° = 250°, т.к. 250° > 180°, то ∠CAD = 360° - 250° = 110°;
2) ∠CAD = 87° + 98° = 185°, т.к. 185° > 180°, то ∠CAD = 360° - 185° = 175°;
3) ∠CAD = 140° + 30° = 170°;
4) ∠CAD = 60° + 70° = 130°.
Ответ: 1) 250°;
2) 175°;
3) 170°;
4) 130°.