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Problems in 3D. OCR Stage 9. What you should know. Pythagoras’ Theorem Trigonometry in right-angled triangles Labelling of sides & angles in triangles. H. C. G. E. F. D. 8cm. A. C. B. A. B. 5cm. Cuboid. Calculate AC. 4cm. 8cm. 5cm. Consider Triangle ABC. C. 8cm. 5cm. A.
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Problems in 3D OCR Stage 9
What you should know • Pythagoras’ Theorem • Trigonometry in right-angled triangles • Labelling of sides & angles in triangles
H C G E F D 8cm A C B A B 5cm Cuboid Calculate AC 4cm 8cm 5cm Consider Triangle ABC
C 8cm 5cm A B Calculate AC AC² = 5² + 8² AC² = 25 + 64 Pythagoras says AC2 = AB2 + BC2 AC² = 89 AC = √89 AC = 9.433…cm AC = 9.43cm
H G E F 4cm D A C 8cm 5cm B Calculate Angle GBC
G 4cm B C 8cm SOH CAH TOA Tan angle GBC = 4 / 8 = 0.5 Tan-1 0.5 = 26.565…º O H Angle GBC = 26. 6º A Consider Triangle GBC
H G E F 4cm D A C 8cm 5cm B Calculate Angle GC 9.43cm
A G 4cm 9.43cm A C 9.43cm G C 4cm SOH CAH TOA Tan angle AGC = 9.43 / 4 Tan-1 (9.43 ÷ 4) = 67.014…º H O Angle AGC = 67.0º A
Wedge A B Angle DBF? DF? E F D C Can make calculations as in a Cuboid Isolate & sketch required triangle