Lesson 6 of 16
Two sides and the corner between them
Show on a big screenTwo lengths and an angle. Is that enough for a triangle?
Flip the switch. Then slide the length.
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The angle must sit between
Yes, if the angle is between the two sides. Then only one triangle fits.
SAS: two sides and the angle between them give one triangle. S is a side and A is an angle. The angle between the sides is the included angle.
Now move the angle so it is not between the sides. This is SSA: side, side, angle. The same numbers can now make two triangles, one triangle, or none.
| Where the other length goes | Triangles that fit |
|---|---|
| A 45 mm side, angle between | Exactly one |
| A 45 mm side opposite the angle | Two. Third sides: 78.1 and 20.2 mm |
| A 30 mm side opposite the angle | None. It cannot reach |
| A 70 mm side opposite the angle | Exactly one. It is longer than the 60 mm side |
Try the lab to finish this lesson.