Finding the Area of a Triangle
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Objective
find area of plane figures
Part 1 of 4
Warm-up video
Math with Mr. J · 4:18Vetted channel
We don't generate video — this one is by Math with Mr. J on YouTube. The practice questions and exit ticket below were drafted by AI for this objective, and every question is editable in the teacher guide.
Part 2 of 4
Key concepts
3 concepts
- 1
To find the area of a shaded region with a triangle inside a square, first find the area of the outside square and then subtract the area of the inside triangle.
- 2
The area of the outside square, with sides of 7 yards each, is found by squaring the side length: 7² = 49 square yards.
- 3
The area of the inside triangle, with a base of 4 yards and a height of 5 yards, is found using the formula: (base × height) / 2 = (4 × 5) / 2 = 10 square yards.
Part 3 of 4
Practice
5 questions
What formula is used to calculate the area of a square when you know the length of one side?
A square has a side length of 8 meters. What is the area of the square?
Part 4 of 4
Exit ticket
Quick comprehension check
“A rectangle with a length of 10 cm and a width of 6 cm has a triangle cut out of it. The triangle has a base of 4 cm and a height of 3 cm. What is the area of the remaining shaded region?”
Sample answer included in the free materials
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Complete lesson plan with answer keys and alternate activities
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