Triangle 1 - Lesson

Triangle - Lesson 1

Open Ended

Why are there two "missing" triangle types in the chart?

Multiple Choice

Is an equilateral triangle also isosceles?

• Yes

• No

Multiple Choice

Can you work out the size of the two missing angles in the picture?

• 40

• 50

• 60

• 70

• 80

Multiple Choice

What is the size of ∠A in the picture?

• 15

• 30

• 45

• 60

• 90

Multiple Choice

Tom's, Bob's, and Fred's houses are in a triangle. Tom's house is 70 ft away from Bob's house. Fred's house is 90 ft away from Bob's house. Fred's house is 50 ft away from Tom's house. What is the shortest distance Tom can travel if he starts from his own house, visits both Fred's and Bob's houses, and then returns home?

• 100

• 140

• 180

• 210

• 240

Multiple Choice

An equilateral triangle has one side with length 18cm. What is the perimeter of the triangle?

• 27

• 54

• 72

• 324

• Not enough information is given.

Multiple Choice

An isosceles triangle measures 4 inches along its two equal sides, and 7

inches along its third side. What is the perimeter of the triangle?

• 10

• 12

• 15

• 17

• 18

Multiple Select

Two sides of an isosceles triangle are 6 inches and 10 inches. Choose all possible perimeters of this triangle (there may be more than one correct answer).

• 16

• 22

• 26

• 31

• 32

Multiple Select

Two sides of an isosceles triangle are 3 inches and 6 inches. Choose all possible perimeters of this triangle (there may be more than one correct answer).

• 10

• 12

• 15

• 18

• 20