Geometry and TrigonometryEasy–MediumBase angle from a vertex angle
Geometry and Trigonometry practice question
A roof truss forms an isosceles triangle whose vertex angle (between the two equal sides) measures 48°. What is the measure, in degrees, of each base angle?
Answer: 66
The base angles are equal and together make 180 − 48 = 132, so each is 66°.
Common wrong answers
- If you answered 42
- 42 is 90 − 48, treating the triangle as right-angled.
- If you answered 48
- 48 is the vertex angle; the base angles are different.
- If you answered 132
- 132 is the sum of BOTH base angles.
More Geometry and Trigonometry questions
- Easy–Medium
A circle has a radius of 6. What is its area? (Use A = πr².) - Easy–Medium
A right triangle has legs of length 6 and 8. What is the length of the hypotenuse? - Easy–Medium
A circle has a radius of 5. What is its circumference? (Use C = 2πr.) - Easy–Medium
What is the midpoint of the segment joining the points (2, 3) and (8, 11)? - Easy–Medium
What is the measure, in degrees, of angle B? - Easy–Medium
What is the area, in square centimeters, of the trapezoid?
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