12.05 Area of triangles
Consider the rectangle shown:
Find the area of the entire rectangle.
Find the area of the triangle.
What do you notice about the two areas?
For each of the following figures:
Find the area of the entire rectangle.
Find the area of the shaded triangle.
Consider the following triangle:
Which dimension of the following rectangle forms the height of the inside triangle?
Find the area of the following triangles:
Find the area of a triangle which has the following dimensions:
For each of the following triangles, find the value of b or h given the area:
Area =20\text{ mm}^2
Area =48\text{ m}^2
Determine whether the following could be the dimensions of a triangle with an area of 20\text{ mm}^2:
Base =8\text{ mm}, height =5\text{ mm}.
Base =1\text{ mm}, height =20\text{ mm}.
Base =5\text{ mm}, height =8\text{ mm}.
Base =2\text{ mm}, height =20\text{ mm}.
Complete the following table of base and height measurements for different triangles, which all have an area of 30\text{ m}^2:
| \text{Base (m)} | 10 | 15 | |
|---|---|---|---|
| \text{Height (m)} | 12 | ||
| \text{Area (m}^2) | 30 | 30 | 30 |
Lisa has purchased a rectangular piece of fabric measuring 6\text{ m} in length and 9\text{ m} in width. Find the area of the largest triangular piece she can cut out from it.
A gutter running along the roof of a house has a cross-section in the shape of a triangle as shown:
If the area of the cross-section is 40\text{ cm}^2, and the length of the base of the gutter is 10\text{ cm}, find the perpendicular height h of the gutter.
The faces on a 4-sided die are all triangular. Each face has a base length of 19\text{ mm} and a perpendicular height of 12\text{ mm}. Find the area of one face.