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Angle Chasing: all problems

Focus mode: every practice problem from the chapter, one after another.

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Problem 29.2.1

AMC 10

Let ABCDEFABCDEF be an equiangular hexagon. The lines AB,CD,AB, CD, and EFEF determine a triangle with area 1923192\sqrt{3}, and the lines BC,DE,BC, DE, and FAFA determine a triangle with area 3243324\sqrt{3}. The perimeter of hexagon ABCDEFABCDEF can be expressed as m+npm + n\sqrt{p}, where m,n,m, n, and pp are positive integers and pp is not divisible by the square of any prime. What is m+n+pm + n + p?

Equiangular hexagon ABCDEF (every angle 120°) with sides 14.76, 6.48, 14.76, 6.48, 14.76, 6.48; perimeter ?; lines AB, CD, EF make an equilateral triangle of side 27.71; lines BC, DE, FA make an equilateral triangle of side 36

ABCDEF
Perimeter = ? (hidden until the end of the example)
Triangle (AB, CD, EF): side 27.71, area 332.55
Triangle (BC, DE, FA): side 36, area 561.18

Equiangular hexagon ABCDEF (every angle 120°) with sides 14.76, 6.48, 14.76, 6.48, 14.76, 6.48; perimeter ?; lines AB, CD, EF make an equilateral triangle of side 27.71; lines BC, DE, FA make an equilateral triangle of side 36

Problem 29.2.2

AMC

Two congruent circles centered at points AA and BB each pass through the other circle's center. The line containing both AA and BB is extended to intersect the circles at points CC and DD. The circles intersect at two points, one of which is EE. What is the degree measure of ∠CED\angle CED?

Problem 29.2.3

AMC 10

Abdul and Chiang are standing 48 feet apart in a field. Bharat is standing in the same field as far from Abdul as possible so that the angle formed by his lines of sight to Abdul and Chiang measures 60∘60^\circ. What is the square of the distance (in feet) between Abdul and Bharat?

Problem 29.2.4

AMC 10

Square ABCDABCD is rotated 20∘20^\circ clockwise about its center to obtain square EFGHEFGH, as shown below. What is the degree measure of ∠EAB\angle EAB?

Problem 29.2.5

MATHCOUNTS

A square is located in the interior of a regular hexagon, and certain vertices are labeled as shown. What is the degree measure of ∠ABC\angle ABC?

Problem 29.2.6

AMC 10

In the given circle, the diameter EB‾\overline{EB} is parallel to DC‾\overline{DC}, and AB‾\overline{AB} is parallel to ED‾\overline{ED}. The angles AEBAEB and ABEABE are in the ratio 4:54 : 5. What is the degree measure of angle BCDBCD?

Problem 29.2.7

AMC 10

The keystone arch is an ancient architectural feature. It is composed of congruent isosceles trapezoids fitted together along the non-parallel sides, as shown. The bottom sides of the two end trapezoids are horizontal. In an arch made with 99 trapezoids, let xx be the angle measure in degrees of the larger interior angle of the trapezoid. What is xx?

Problem 29.2.8(additional)

AHSME

△ABC\triangle ABC is isosceles with base ACAC. Points PP and QQ are respectively in CBCB and ABAB and such that AC=AP=PQ=QBAC = AP = PQ = QB. The number of degrees in ∠B\angle B is:

Problem 29.2.9(additional)

AHSME

In this diagram ABAB and ACAC are the equal sides of an isosceles △ABC\triangle ABC, in which is inscribed equilateral △DEF\triangle DEF. Designate ∠BFD\angle BFD by aa, ∠ADE\angle ADE by bb, and ∠FEC\angle FEC by cc. Then:

Click a choice or type its letter (A–E).

Problem 29.2.10(additional)

AMC 10

This problem also appears in the book as 15.1.9.

How many non-similar triangles have angles whose degree measures are distinct positive integers in arithmetic progression?

Problem 29.2.11(additional)

MATHCOUNTS

Concave quadrilateral ABCDABCD is symmetric about the line ACAC. The measures of angles DABDAB and ABCABC are 8484 degrees and 3232 degrees, respectively. The dashed line segments bisect angles ABCABC and ADCADC. What is the degree measure of the acute angle at which the two dashed line segments intersect?

Problem 29.2.12(additional)

AMC 10/12

As shown in the figure below, point EE lies on the opposite half-plane determined by line CDCD from point AA so that ∠CDE=110∘\angle CDE = 110^\circ. Point FF lies on AD‾\overline{AD} so that DE=DFDE = DF, and ABCDABCD is a square. What is the degree measure of ∠AFE\angle AFE?

Problem 29.2.13(additional)

AHSME

In the adjoining figure, ABCDABCD is a square, ABEABE is an equilateral triangle and point EE is outside square ABCDABCD. What is the measure of ∡AED\measuredangle AED in degrees?

Problem 29.2.14(additional)

AMC 10

The angles of quadrilateral ABCDABCD satisfy ∠A=2∠B=3∠C=4∠D\angle A = 2\angle B = 3\angle C = 4\angle D. What is the degree measure of ∠A\angle A, rounded to the nearest whole number?

Problem 29.2.15(additional)

AMC 10

The sum of two angles of a triangle is 65\frac{6}{5} of a right angle, and one of these two angles is 30∘30^\circ larger than the other. What is the degree measure of the largest angle in the triangle?

Problem 29.2.16(additional)

AMC 10

This problem also appears in the book as 15.1.8.

Mary divides a circle into 1212 sectors. The central angles of these sectors, measured in degrees, are all integers and they form an arithmetic sequence. What is the degree measure of the smallest possible sector angle?

Problem 29.2.17(additional)

AHSME

An acute isosceles triangle, ABCABC, is inscribed in a circle. Through BB and CC, tangents to the circle are drawn, meeting at point DD. If ∠ABC=∠ACB=2∠D\angle ABC = \angle ACB = 2\angle D and xx is the radian measure of ∠A\angle A, then x=x =

Problem 29.2.18(additional)

AIMEChallenge

Triangle ABCABC is isosceles with AC=BCAC = BC and ∠ACB=106∘\angle ACB = 106^\circ. Point MM is in the interior of the triangle so that ∠MAC=7∘\angle MAC = 7^\circ and ∠MCA=23∘\angle MCA = 23^\circ. Find the number of degrees in ∠CMB\angle CMB.

Problem 29.2.19(additional)

AMC 10Challenge

Quadrilateral ABCDABCD has AB=BC=CDAB = BC = CD, angle ABC=70∘ABC = 70^\circ and angle BCD=170∘BCD = 170^\circ. What is the measure of angle BADBAD?

Problem 29.2.20(additional)

AIMEChallenge

A beam of light strikes BC‾\overline{BC} at point CC with angle of incidence α=19.94∘\alpha = 19.94^\circ and reflects with an equal angle of reflection as shown. The light beam continues its path, reflecting off line segments AB‾\overline{AB} and BC‾\overline{BC} according to the rule: angle of incidence equals angle of reflection. Given that β=α/10=1.994∘\beta = \alpha/10 = 1.994^\circ and AB=BCAB = BC, determine the number of times the light beam will bounce off the two line segments. Include the first reflection at CC in your count.