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Lesson Example Discussion Quiz: Class Homework

Step-5

Title: Perimeter of Triangle(based on sides)

Grade: 4-a Lesson: S1-L7

Explanation: Hello Students, time to practice and review the steps for the problem.

Lesson Steps

Step	Type	Explanation	Answer
1	Problem	If the perimeter of a triangle is 45 feet and two of the side lengths are 10 feet and 15 feet, what is the length of the third side?
2	Formula	Perimeter of triangle	P = a + b + c
3	Step	The side lengths of a triangle are	10 ft , 15 ft
4	Step	Given Perimeter of triangle is	45 ft
5	Step	Substitute the values	45 = 10 + 15 + c
6	Step	Now ,we need to determine the length of the third side of the triangle(c),	c = 45 - 25
7	Step	After simplification	c = 20
8	Step	The length of the third side of the triangle is 20 feet.
9	SumUp	Can you summarize what you’ve understood in the above steps?
10	Choice.A	This is not correct because it does not satisfy the triangle inequality theorem	10 feet
11	Choice.B	This is correct because it satisfies the triangle inequality theorem	20 feet
12	Choice.C	This is not correct because it does not satisfy the triangle inequality theorem	13 feet
13	Choice.D	This is not correct because it does not satisfy the triangle inequality theorem	65 feet
14	Answer	Option	B
15	SumUp	Can you summarize what you’ve understood in the above steps?

Step

Type

Explanation

Answer

Problem

If the perimeter of a triangle is 45 feet and two of the side lengths are 10 feet and 15 feet, what is the length of the third side?

Formula

Perimeter of triangle

P = a + b + c

Step

The side lengths of a triangle are

10 ft , 15 ft

Step

Given Perimeter of triangle is

45 ft

Step

Substitute the values

45 = 10 + 15 + c

Step

Now ,we need to determine the length of the third side of the triangle(c),

c = 45 - 25

Step

After simplification

c = 20

Step

The length of the third side of the triangle is 20 feet.

SumUp

Can you summarize what you’ve understood in the above steps?

Choice.A

This is not correct because it does not satisfy the triangle inequality theorem

10 feet

Choice.B

This is correct because it satisfies the triangle inequality theorem

20 feet

Choice.C

This is not correct because it does not satisfy the triangle inequality theorem

13 feet

Choice.D

This is not correct because it does not satisfy the triangle inequality theorem

65 feet

Answer

Option

SumUp

Can you summarize what you’ve understood in the above steps?