Enough to Find It?

Part of the Polygons & Quadrilaterals section of Coddy's Geometry journey. Lesson 50 of 61.

Before working, ask whether the figure gives enough. A composite area needs every piece, and every piece needs its lengths. A missing length may still follow from the others: opposite sides of a rectangle are equal, and the pieces of a side add up to the whole side.

$An L-shape with AB = 10, BC = 2 and EF = 4, and no height for the top part$

This L-shape gives the bottom rectangle, 10 by 2. The top rectangle is 4 wide, but nothing gives its height: neither DE nor the whole left side FA is labelled. Stretch the top part taller and every label stays true while the area grows. So the area is not fixed. A label on DE, the top part's height, would fix it.

Challenge

The L-shape ABCDEF is cut by DG into two rectangles. AB = 8, BC = 3, EF = 3, and the whole left side FA = 7. Does the figure give enough to fix the area of the L-shape? Answer, then press Check.

Try it yourself

$Is there enough information?$

Is there enough information?

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

Regular Polygons From an Angle to the Sides Inside a Regular Polygon Recap: Regular Polygons

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