The perimeter of a triangle DEF is 81 units. The length of side DE is twice the length of side EF, and the length of side DF is 4 units

Question

The perimeter of a triangle DEF is 81 units. The length of side DE is twice the length of side EF, and the length of side DF is 4 units less than the length of side DE. Let s represent the length, in units, of side EF. Write an equation that can be used to find s

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Natalia 2 months 2021-10-14T02:52:17+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-10-14T02:53:21+00:00

    Answer:

    5s = 85

    Step-by-step explanation:

    Perimeter of our triangle = DE + EF + DF = 81 units

    We know from the question that

    The length of side DE is twice the length of side EF

    DE = 2EF

    and the length of side DF is 4 units less than the length of side DE

    DF = DE – 4

    We can replace EF with s in our equations

    DE = 2s

    And now we can replace DE from the other equation

    DF = DE – 4

    DF = 2s – 4

    If the perimeter of our triangle = DE + EF + DF = 81 units

    We will replace the sides with our new values

    Perimeter = 2s + s + 2s – 4 = 81

    We can put this as our answer, or we can simplify further

    Simplify by adding 4 to both sides

    2s + s + 2s – 4 + 4 = 81 + 4

    Simplify

    2s + s + 2s = 85

    Simplify

    5s = 85

    Since the question only asked for an equation, not for us to solve it, we can stop here

    (If you wanted to solve for s, just divide both sides by 5)

    5s / 5 = 85 / 5

    s = 17

    0
    2021-10-14T02:53:56+00:00

    Answer:

    81 = s + 2s + (2s -4)

    Step-by-step explanation:

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