Examples with solutions for Angles in Parallel Lines: Isosceles triangle

Exercise #1

CD is parallel to AB.

What type of triangle is ABC?

ααααααDDDCCCAAABBB

Video Solution

Answer

Isosceles, AB = BC

Exercise #2

ABCD rectangle.

What type of triangle is EFG?

AAABBBCCCDDDEEEFFFGGG7334

Video Solution

Answer

Isosceles EG=GF

Exercise #3

AB is parallel to DE.

AC = CB

Calculate the size of angle CDF.

FFFAAABBBEEEDDDCCC115

Video Solution

Answer

122.5

Exercise #4

AB and CD parallel

Given AC=AD

Find X

BBBAAACCCDDD2X-7X+15

Video Solution

Answer

22 22

Exercise #5

b ,a parallel.

BC=BD

?=X

aaabbbBBBDDDCCCAAAx+42x-8

Video Solution

Answer

12

Exercise #6

Lines a and b are parallel.

The triangle ABC is isosceles.

What are the sizes of its angles?

767676636363353535aaabbbBBBAAACCC

Video Solution

Answer

41, 41, 98

Exercise #7

b,a parallel.

AB=AC

?=X

aaabbbBBBAAACCC67

Video Solution

Answer

±6

Exercise #8

CE is parallel to AD.

What is the value of X given that ABC is isosceles and AB = BC?

DDDEEEBBBAAACCC2XX-103X-30

Video Solution

Answer

56.67

Exercise #9

AB = BC

a, b, and c parallel to one another

Calculate the angles of the triangle ABC.

aaabbbcccBBBAAACCC135α145

Video Solution

Answer

50, 50, 80

Exercise #10

AB is parallel to CD.

Which triangle is isosceles?

XXXXXXXXXYYYYYYAAABBBCCCDDD

Video Solution

Answer

ABC, AB = BC

Exercise #11

AD is parallel to BC.
AE is an extension of side BA.

What type of triangle is ABC?

XXXXXXAAABBBCCCDDDEEEFFF90-X

Video Solution

Answer

Isosceles.

Exercise #12

ABC is an isosceles triangle.

DE is parallel to BC.

Angle A is equal to 3X plus 22.

Express the size of angle DEC.

AAABBBCCCDDDEEE

Video Solution

Answer

101+1.5x 101+1.5x