Post a New Question

Maths

posted by .

I am trying to work out the area and perimeter of an equilateral triangle but am only given the altitude (12cm), i have tried everything from c^2 = a^2 + b^2 to b x h / 2 and nothing seems to work. How do i work this out with only one measurement?

  • Maths -

    Since you know it is equilateral also, the length of a side (c) must be given by c^2 = 12^2 + (c/2)^2
    (3/4)c^2 = 12^2
    c = 12/[(1/2)sqrt3] = 18.856
    You could also write it at 12/sin60
    Area = (1/2)(12)(18.856) = ?
    Perimeter = 3 c = ?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Math Homework

    1) Given the side of a square pyramid is 6cm and the altitude is 4cm calculate the surface area. 2) Given the side of a square pyramid is 12cm and the altitude is 8cm calculate the surface area. 3) Given the side of a square pyramid …
  2. Maths

    The altitude of an equilateral triangle is 12cm. Find the length of the sides.
  3. Math

    An equilateral triangle s divided into 4 congruent equilateral triangles. What method can be used to find the area of the larger equilaterl triangle give the area of one of the smaller triangles?
  4. MATHS,7TH CLASS

    A RIGHT ANGLED TRIANGLE ABC IS GIVEN,WHERE AB IS 5CM,AC IS 12CM,BC IS 13CM,AD IS AN ALTITUDE FROM A TO BC,FIND THE AREA OF THE TRIANGLE AND FIND AD ALSO.
  5. maths

    perimeter of a equilateral triangle is given as 42 cm. Find the perimeter of a shaded part of triangle if the 3 sectors of a circle marked are identical
  6. geometry

    ok i have 2 problems and id appreciate it if someone can help :) 1. given hexagon ABCDEF with diagonal AC being 2 calculate the area and perimeter of the hexagon. 2. the perimeter of an equilateral triangle is equal to its area. find …
  7. geometry

    An equilateral triangle has an altitude of 15m. What is the perimeter of the triangle. Could someone please explain how to find perimeter. I believe the answer to be 60 sq rt 3m
  8. Geometry

    Find the area of each equilateral triangle. The triangle has 12cm sides. The triangle has 10in altitudes.
  9. Geometry

    The top of a valentine candy box is in the shape of an equilateral triangle if the altitude of the triangle is 8cm what is the perimeter of the triangle
  10. Maths

    Work out the area of an equilateral triangle, with side lengths a, in sure form.

More Similar Questions

Post a New Question