Area of Triangle

“The child sees triangle ACB = triangle ADB, and that I + II = CA - DB; and so he sees that the area of triangle=1/2 area of rectangle whose base and altitude are the same as those of the triangles.” -Foster, 1921

Keywords

rectangle, right triangles, equal triangles, triangle area, half base times height

Galleries

Miscellaneous Triangles

Source

Ellsworth D. Foster ed. The American Educator (vol. 1) (Chicago, IL: Ralph Durham Company, 1921)

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