ISEE Lower Level Math : Geometry

Study concepts, example questions & explanations for ISEE Lower Level Math

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Example Questions

Example Question #3 : How To Find The Perimeter Of A Triangle

Use the triangle to answer the question.

Triangle_perimeter_2

What is the perimeter of the triangle?

Possible Answers:

Correct answer:

Explanation:

To find the perimeter, add all the sides together.

Example Question #4 : How To Find The Perimeter Of A Triangle

An equilateral triangle has a side length equal to .

What is the perimeter of the triangle?

Possible Answers:

Correct answer:

Explanation:

Because it is an equilateral triangle, all sides have the same length .

The perimeter is the sum of the length of the sides.

Isee_question_11

Example Question #5 : How To Find The Perimeter Of A Triangle

Set_3b

Figure not drawn to scale 

The perimeter of isosceles triangle is .

If  and  are equal to each other and is , what is the length of ?

Possible Answers:

Correct answer:

Explanation:

The perimeter of the triangle is equal to the sum of the lengths of all the sides.

Because the triangle is an isosceles triangle, the triangle has two equal sides, which we know are and 

Since is the same as , we can say: .

We now solve for :

Subtract  from both sides

Divide both sides by 

Example Question #4 : How To Find The Perimeter Of A Triangle

What is the name of the longest side of a right triangle?

Possible Answers:

Hypotenuse

Obtuse

Base

Equilateral

Length

Correct answer:

Hypotenuse

Explanation:

The hypotenuse is the longest side of a triangle with a right angle.

All the other terms refer to something else. Obtuse refers to an angle over 90 degrees. Length is too general of a term, and refers to the measurement of any given side. Equilateral refers to a triangle in which all angles and side are of equal measurement. Base refers to the side that is perpendicular to the measure of the height, meaning that it will be one of the shorter sides.

Example Question #342 : Geometry

In an isosceles triangle, two side are 4 feet long. Which of the following is NOT a possible length of the third side?

Possible Answers:

5 feet

2.5 feet

8 feet

1 foot

7 feet

Correct answer:

8 feet

Explanation:

For triangles, it is impossible for a third side to be equal to or greater than the sum of the two other sides.

Given that the sum of the two sides of this triangle is 8, it is impossible for the third side to be equal to 8 feet.

Example Question #5 : How To Find The Perimeter Of A Triangle

In an equilateral triangle, the perimeter is 42. What is the length of 1 side?

Possible Answers:

Correct answer:

Explanation:

In an equilateral triangle, all 3 sides are equal to one another. Therefore, if the perimeter is 42, the length of 1 side will be equal to 42 divided by 3. This results in 14, which is therefore the correct answer. 

Example Question #6 : How To Find The Perimeter Of A Triangle

If the side of an equilateral triangle is equal to  and the perimeter is equal to 18, what is the value of ?

Possible Answers:

Correct answer:

Explanation:

The three sides must sum to 18:

Combine like terms on the left:

Divide both sides by 9:

Example Question #5 : How To Find The Perimeter Of A Triangle

If an equilateral triangle has sidelengths of 3 inches, what is the perimeter?

Possible Answers:

Correct answer:

Explanation:

An equilateral triangle is a speical type of triangle that has three congruent sides; in other words, all sides are the same length. 

Therefore the perimeter for an equilateral triangle can be written as .

Plug in the sidelength given in the question to find the perimeter:

Example Question #1281 : Isee Lower Level (Grades 5 6) Mathematics Achievement

If the sides of a triangle are equal to 5, 6, and 2x, what is the value of x if the perimeter is 23?

Possible Answers:

Correct answer:

Explanation:

The perimeter of a triangle is equal to the sum of its sides. Given that the sides are equal to 5, 6, and 2x, and the perimeter is 23, the appropriate equation to use would be:

(Subtract 11 from each side of the equation.)

(Divide each side of the equation by 2.)

Example Question #341 : Geometry

What is the perimeter of an equilateral triangle for which each side is equal to 4.5?

Possible Answers:

Correct answer:

Explanation:

The perimeter is equal to the sum of the sides of the shape. For an equilateral, all sides are equal. This allows us to simply multiply the given length by 3.

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