12 multiple-choice questions, progressively harder.
PX is perpendicular to line ℓ\ellℓ and X lies on ℓ\ellℓ. PX is 8 cm. A slanted segment PY reaches another point Y on ℓ\ellℓ and is 10 cm. What is the distance from P to ℓ\ellℓ?
Solution
Correct answer: B
The distance to a line is measured along the perpendicular. PX supplies that measurement, while PY is slanted.
P is on the internal bisector of angle UOV. PX and PY are perpendiculars to the two side lines. If PX is 8.5 cm, what is PY?
Correct answer: D
The internal angle-bisector equidistance theorem gives PX=PYPX=PYPX=PY. Therefore PY is 8.5 cm.
Which lines meet at a triangle's incenter?
Correct answer: A
The incenter is the common point of the internal angle bisectors. Perpendicular bisectors instead locate the circumcenter.
I is the incenter. F is the perpendicular foot on a side. IF is 3 cm, while a segment from I to a vertex is 9 cm. What is the inradius?
Correct answer: C
The inradius is the common perpendicular distance from the incenter to the sides. IF, rather than the segment to a vertex, is that distance.
P lies on an internal angle bisector and X,Y are the perpendicular feet. Which facts prove triangles OXP and OYP congruent by AAS?
The right angles match, the bisector gives equal vertex angles, and OP is a common nonincluded side. Those are the two angle pairs and side needed for AAS.
An arc centered at O meets two side rays at U and V. Why is OU equal to OV?
The compass keeps the same radius as the arc meets each ray. Both OU and OV are radii of that first circle.
P is strictly inside an angle less than 180 degrees. Its perpendicular distances to the two side lines are equal. What follows?
The interior-point converse applies: equal perpendicular distances from an interior point place it on the internal bisector.
The perpendicular from P to the supporting line AB lands beyond B. Which length measures the distance from P to line AB?
The supporting line extends through and beyond both vertices. Its perpendicular foot measures distance to the full line, even when the foot is outside segment AB.
Where is the incenter of an obtuse triangle?
Internal bisectors meet at a point inside the triangle. The incenter remains interior for acute, right and obtuse triangles.
Ray BR internally bisects an angle measuring 62∘62^\circ62∘. What is either half-angle?
Bisecting makes two equal parts.
The incircle of triangle ABC has center I, and IF is perpendicular to side AB at F. How many points does the incircle share with side AB?
The incircle touches each side once. Its point on AB is the perpendicular foot F, so exactly one point is shared.
Which comparison belongs to the incenter theorem?
An incenter is equally far from the three sides when distances are measured perpendicularly. Equal distances to vertices describe a circumcenter.
Reset this practice set?
This clears every answer you have given and starts the set again from question 1.