Rectangle and Triangle

Part of the Polygons & Quadrilaterals section of Coddy's Geometry journey. Lesson 48 of 61.

A piece does not have to be a rectangle. A house shape is a rectangle with a triangle on top, and the dashed line between them is the cut. Each piece has its own rule.

$A house shape: a rectangle with a triangle roof, cut along DC; the roof height is 6$

Here the rectangle ABCD has sides 8 and 4, area 32. The roof triangle DCE has base DC = 8 and height EF = 6, so its area is 1/2 × 8 × 6 = 24. The whole shape: 32 + 24 = 56. The triangle's height is the dashed EF at right angles to DC, never a slanted side.

Challenge

The house shape ABCED is a rectangle ABCD with the roof DCE on top, cut along DC = 8. BC = 5 and the roof height EF = 3. Find the area of the whole shape, then press Check.

Try it yourself

$Find the marked part of the figure$

Find the marked part of the figure

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Polygons & Quadrilaterals

2Regular Polygons

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5Rectangles, Rhombi, Squares

Rectangles The Diagonal of a Rectangle Rhombus Angles Squares Recap: Special Parallelograms

8Area of Parallelograms

Area of a Rectangle A Side from the Area Slide the Top Area of a Parallelogram Recap: Parallelogram Area

11Polygon Chases

Parallel Sides in a Pentagon Marks, Not Looks Pentagon with x Regular Shapes Together Recap: Polygon Chases