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ABC is an isosceles triangle with a perimeter
of 74 cm. how long is the longest side of this
triangle?
A. 10 cm
B. 17 cm
C. 20 cm
D. 27 cm

ABC is an isosceles triangle with a perimeter of 74 cm how long is the longest side of this triangle A 10 cm B 17 cm C 20 cm D 27 cm class=

Respuesta :

Answer:

  • 27 cm

Step-by-step explanation:

Given

  • ABC is isosceles
  • The sides are, AB = 3x - 3, AC = 3x - 3 and BC = 2x
  • The perimeter is, P = 74 cm

Find the value of x first

Use the perimeter formula

  • P = a + b + c, where a, b and c are sides of the triangle

Substitute known values to get the equation

  • 3x - 3 + 3x - 3 + 2x = 74
  • 8x - 6 = 74
  • 8x = 80
  • x = 10

Find the sides

  • AB = AC = 3*10 - 3 = 27 cm
  • BC = 2*10 = 20 cm

As we see the longest side is 27 cm