10.4a Lesson Areas of Triangles and Quadrilaterals

10.4a Areas of Triangles and Quadrilaterals

Finite Math

EQ: Wednesday, November 15, 2023

• How do I find the area of triangles and quadrilaterals using a basic formula?

Area - the size of a flat (2D) space

− measured in square units

Area - the size of a flat (2D) space

− measured in square units

​

Basic Formula for Area

Multiply Perpendicular Measurements

​Conversion Between Units

12 in = 1 foot
1 yard = 3 feet
100 cm = 1 m
1000 mm = 1 m
10 mm = 1 cm
1000 m = 1 km
5280 feet = 1 mile

Basic Area Formula

Name the polygon and find its the area.

Applying Basic Area Formula to Triangles

Applying Basic Area Formula to Triangles

Applying Basic Area Formula to Triangles

Applying Basic Area Formula to Triangles

Math Response

Find the area of the triangle.

Type answer here

Correct Answer: 60

Deg^°

Rad

Applying Basic Area Formula to Parallelograms

Math Response

Find the area of the parallelogram.

Type answer here

Correct Answer: 40

Deg^°

Rad

Applying Basic Area Formula to Trapezoids

a and b are parallel sides
h is perpendicular distance

Applying Basic Area Formula to Trapezoids

Math Response

Find the area of the trapezoid.

Type answer here

Correct Answer: 275

Deg^°

Rad

Areas of Quadrilaterals and Triangles

Parallelogram/Rectangle:

Trapezoid:

Triangle:

​Rationale: product of perpendicular measurements

​Rationale: sum of parallel sides gives twice the area

​Rationale: product of perpendicular measurements, gives twice the area

Multiple Choice

Find the area of the figure.

• 18.2 square yards

• 13.1 square yards

• 4.6 square yards

• 9.1 square yards

Multiple Choice

Find the area of the figure.

• 8.875 square feet

• 6.675 square feet

• 3.3 square feet

• 17.75 square feet

Multiple Choice

Find the missing measurement if the area is 20.5 square yards.

• 7.8 yards

• 9.1 yards

• 6.6 yards

• 8.2 yards

Multiple Choice

Find the missing measurement if the area is 12.4 square feet.

• 6.7 ft

• 4.2 ft

• 9.4 ft

• 7.8 ft

Multiple Choice

Find the area of the figure.

• 94.7 square meters

• 200 square meters

• 100 square meters

• 86.5 square meters

Multiple Choice

Find the missing measurement if the area is 49 square yards.

• 7 yd

• 2.3 yd

• 4.7 yd

• 5.4 yd

Multiple Choice

Find the area of the figure.

• 165 square yards

• 80 square yards

• 41.3 square yards

• 82.5 square yards

Multiple Choice

Find the area of the figure.

• 16.94 km^2

• 23.04 km^2

• 19.54 km^2

• 33.88 km^2

Multiple Choice

Find the area of the figure.

• 19.3 in^2

• 38.5 in^2

• 37.3 in^2

• 77 in^2

Multiple Choice

Find the missing measurement if the area is 25.2 m^2.

• 4.2 m

• 5.2 m

• 2.8 m

• 3 m