📚 Topic Summary
The base and height are fundamental when calculating the area of 2D shapes. The base is typically the side on which the shape 'sits', but it can be any side. The height is the perpendicular distance from the base to the opposite vertex or side. It's crucial that the height forms a right angle ($90^{\circ}$) with the base. For triangles, the height goes from the base to the opposite vertex. For parallelograms and trapezoids, it's the perpendicular distance between the bases. Getting these right helps avoid area calculation mistakes!
🧮 Part A: Vocabulary
Match the term with its correct definition:
| Term |
Definition |
| 1. Base |
A. The perpendicular distance from the base to the opposite vertex or side. |
| 2. Height |
B. A four-sided flat shape with straight sides that has a pair of opposite sides parallel |
| 3. Perpendicular |
C. Intersecting at or forming right angles ($90^{\circ}$). |
| 4. Triangle |
D. Often the side on which the shape 'sits'; can be any side. |
| 5. Trapezoid |
E. A three-sided polygon. |
(Answers: 1-D, 2-A, 3-C, 4-E, 5-B)
✍️ Part B: Fill in the Blanks
Complete the sentences using the words provided: perpendicular, base, height, $90^{\circ}$, vertex.
- The _______ is often the side a shape rests on, but any side can serve as one.
- The _______ is measured as the distance from the base to the opposite _______.
- The height must be _______ to the base, forming a _______ angle.
(Answers: 1-base, 2-height, vertex, 3-perpendicular, $90^{\circ}$)
🤔 Part C: Critical Thinking
Explain in your own words why it is important for the height of a triangle to be perpendicular to the base when calculating its area. What happens if you use a non-perpendicular line instead?
