## Tuesday, April 5, 2011

### practice for the take home and in class triangle identification problems

Part A) In all the following problems where triangles are defined by lengths, we will use the number 11 and the other numbers must be whole numbers.

obtuse and isosceles: 11, 11, _____
acute and isosceles: 11, 11, _____
obtuse and scalene: 11, ___, ___
right and scalene: 11, ____, ____ (hint: 11 will be one of the legs.)
acute and scalene: 11, ____, ____

Part B) In all the following problems where triangles are defined by angles, we will use one angle of 34° and the other numbers must be whole numbers.

obtuse and isosceles: 34°, ____, _____
acute and isosceles: 34°, ____, _____
obtuse and scalene: 34°, ___, _____ (many correct answers.)
right and scalene: 34°, ____, ____
acute and scalene: 34°, ____, ____ (many correct answers.)

#### 1 comment:

Prof. Hubbard said...

Part A) In all the following problems where triangles are defined by lengths, we will use the number 11 and the other numbers must be whole numbers.

obtuse and isosceles:
anything from 11, 11, 16 to 11, 11, 21

acute and isosceles:
anything from 11, 11, 1 to 11, 11, 15

obtuse and scalene:
11, 12, 17 (many possible answers)

right and scalene: 11, ____, ____ (hint: 11 will be one of the legs.)
we want a² + 11² = (a+1)². When we do the math, this means

a² + 121 = a² + 2a + 1, so
121 = 2a + 1
120 = 2a
60 = a
11, 60, 61 is a right triangle.

acute and scalene:
11, 12, 13 is one of many correct answers.

Part B) In all the following problems where triangles are defined by angles, we will use one angle of 34° and the other numbers must be whole numbers.

obtuse and isosceles:
34°, 34°, 112°

acute and isosceles:
34°, 73°, 73°

obtuse and scalene:
34°, 100°, 46°