GEOMETRY – Area of Triangles Let’s take a look first at the area of a right triangle. Recall, a right triangle contains a 90 degree or “right” angle. It’s area is easily calculated.

GEOMETRY – Area of Triangles Let’s take a look first at the area of a right triangle. Recall, a right triangle contains a 90 degree or “right” angle. It’s area is easily calculated. The height and base will ALWAYS be the sides that create the right angle. They are interchangeable which means you could switch the labels… height base

GEOMETRY – Area of Triangles Let’s take a look first at the area of a right triangle. Recall, a right triangle contains a 90 degree or “right” angle. It’s area is easily calculated. The height and base will ALWAYS be the sides that create the right angle. They are interchangeable which means you could switch the labels… height base If you cut a rectangle in half, you get 2 right triangles.

GEOMETRY – Area of Triangles Let’s take a look first at the area of a right triangle. Recall, a right triangle contains a 90 degree or “right” angle. It’s area is easily calculated. The height and base will ALWAYS be the sides that create the right angle. They are interchangeable which means you could switch the labels… height base If you cut a rectangle in half, you get 2 right triangles. So each triangle would be half of the rectangles area.

GEOMETRY – Area of Triangles Let’s take a look first at the area of a right triangle. Recall, a right triangle contains a 90 degree or “right” angle. It’s area is easily calculated. The height and base will ALWAYS be the sides that create the right angle. They are interchangeable which means you could switch the labels… height base This is how we get the formula for the area of a right triangle…

GEOMETRY – Area of Triangles EXAMPLE # 1 : Find the area of the given triangle : 10 ft 4 ft

GEOMETRY – Area of Triangles EXAMPLE # 1 : Find the area of the given triangle : 10 ft 4 ft

GEOMETRY – Area of Triangles EXAMPLE # 2 : Find the area of the given triangle : 32 m 25 m

GEOMETRY – Area of Triangles EXAMPLE # 2 : Find the area of the given triangle : 32 m 25 m

A = 225 sq ft GEOMETRY – Area of Triangles EXAMPLE # 3 : Find the base of the given triangle : x A = 225 sq ft 28 ft

A = 225 sq ft GEOMETRY – Area of Triangles EXAMPLE # 3 : Find the base of the given triangle : x A = 225 sq ft 28 ft Any decimal answer gets rounded to 2 decimal places…

GEOMETRY – Area of Triangles Because we also have acute and obtuse triangles, we need a way to calculate their areas. We will look for an “altitude” to use as the height. It makes sense, altitude is how high something is off the ground or “base”. The altitude will always create a 90 degree angle with the base Acute Obtuse altitude base base

GEOMETRY – Area of Triangles Because we also have acute and obtuse triangles, we need a way to calculate their areas. We will look for an “altitude” to use as the height. It makes sense, altitude is how high something is off the ground or “base”. The altitude will always create a 90 degree angle with the base Acute Obtuse altitude base base The formula for area is still the same…

GEOMETRY – Area of Triangles EXAMPLE : Find the area of the given triangle : 10 m 9 m altitude = height

GEOMETRY – Area of Triangles EXAMPLE : Find the area of the given triangle : 10 m 9 m altitude = height

GEOMETRY – Area of Triangles EXAMPLE # 2 : Find the area of the given triangle : 16 in. 11 in. altitude = height

GEOMETRY – Area of Triangles EXAMPLE # 2 : Find the area of the given triangle : 16 in. 11 in. altitude = height

GEOMETRY – Area of Triangles The last type of triangle we need to look at is an equilateral triangle. Equilateral triangles have equal sides AND angles ( all 60 degrees ). 60 S S 60 60 S

GEOMETRY – Area of Triangles The last type of triangle we need to look at is an equilateral triangle. Equilateral triangles have equal sides AND angles ( all 60 degrees ). If we draw an altitude anywhere in our triangle, we create two 30 – 60 – 90 triangles. We also cut one sides distance in half. 60 S S 60 60 S

GEOMETRY – Area of Triangles The last type of triangle we need to look at is an equilateral triangle. Equilateral triangles have equal sides AND angles ( all 60 degrees ). If we draw an altitude anywhere in our triangle, we create two 30 – 60 – 90 triangles. We also cut one sides distance in half. 60 Recall in a 30 – 60 – 90 triangle the medium length side is the square root of three times larger than the smallest side. S S 60 60 S

GEOMETRY – Area of Triangles The last type of triangle we need to look at is an equilateral triangle. Equilateral triangles have equal sides AND angles ( all 60 degrees ). If we draw an altitude anywhere in our triangle, we create two 30 – 60 – 90 triangles. We also cut one sides distance in half. 60 Since the sort side = the middle side or the altitude would be : S S 60 60 S

GEOMETRY – Area of Triangles The last type of triangle we need to look at is an equilateral triangle. Equilateral triangles have equal sides AND angles ( all 60 degrees ). If we draw an altitude anywhere in our triangle, we create two 30 – 60 – 90 triangles. We also cut one sides distance in half. 60 Using the original formula using an altitude we can now find the formula for the area of an equilateral triangle : S S height 60 60 S base

GEOMETRY – Area of Triangles Area of Equilateral triangles : EXAMPLE : Find the area of an equilateral triangle with sides of 12 : 12 12 12

GEOMETRY – Area of Triangles Area of Equilateral triangles : EXAMPLE : Find the area of an equilateral triangle with sides of 12 : 12 12 12