Question

An equilateral triangle has sides 12cm in length. Calculate the

perpendicular height of the triangle. (to the nearest mm)
Help please

Answer 1

Answer: 3.5 cm or 35 mm

Explanation:

12/3 =4 for each side of triangle

cutting the triangle in half, bottom side(a) 4 becomes 2

2^2 + b^2 = 4^2

4 + b^2 = 16

subtract 4 from both sides

b^2 = 12

b = 3.464 cm or 3.5 cm

convert 3.5 cm to 35 mm

Answer 2

10 mm

Explanation:

Draw an equilateral triangle. Label each side 12 mm.

Draw one altitude from one vertex perpendicular to the opposite side. Label the length of the altitude h.

The altitude divided the opposite side into two congruent segments, each one measuring 6 mm.

Now use the Pythagorean Theorem.

a² + b² = c²

(6 mm)² + h² = (12 mm)²

36 mm² + h² = 144 mm²

h² = 144 mm² - 36 mm²

h² = 108 mm²

h = 6√3 mm

h ≈ 10 mm