Basic Geometry : Plane Geometry

Study concepts, example questions & explanations for Basic Geometry

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Example Questions

Example Question #5 : How To Find The Length Of The Side Of A 45/45/90 Right Isosceles Triangle

 is a  triangle.

Triangles_5

What is the length of ?

Possible Answers:

There is not enough information given to answer this question.

Correct answer:

Explanation:

We know that the sides of  triangles are in the ratio of , where the shorter sides lies opposite the  angles, and the longer side is the hypotenuse and lies opposite the right angle. We are given that the hypotenuse is .

Divide the length of the hypotenuse by  to calculate the ratio of magnification.

Multiply the length of the shorter sides by the ratio of magnification.

So the length of  (and ) is .

Example Question #3 : How To Find The Length Of The Side Of A 45/45/90 Right Isosceles Triangle

The following image is not to scale.

Find the length of one of the legs of the right triangle. 

Find_the_leg_length

Possible Answers:

Correct answer:

Explanation:

Find_the_leg_length

Because of the tick marks on both legs, we can determine that this right triangle is a 45/45/90 triangle. Because the length of both legs are the same, this means that the angle opposite of each leg is also the same. 

45/45/90 triangles are special, just like 30/60/90 triangles. Solving for one of the leg lengths can be determined easily through remembering the following:

Find_the_leg_length_resolution

Using this and the 7ft, we can solve for "s" which will provide us with the leg length. 

 while this is the correct answer, the options provided are represented as simplified radicals. 

Example Question #1151 : Plane Geometry

If the hypotenuse of a right isosceles triangle is , what is the length of a side of the triangle?

Possible Answers:

Correct answer:

Explanation:

A right isosceles triangle is also a  triangle.

13

To find the length of a side, we will need to use the Pythagorean Theorem:

Since this is an isosceles triangle, 

The Pythagorean Theorem can then be rewritten as the following:

Since we are trying to find the length of a side of this triangle, solve for .

Simplify.

Multiply the fraction by one in the form of .

Solve.

Now, substitute in the length of the hypotenuse in for  to solve for the side of the triangle in the question.

Simplify.

Reduce.

Example Question #2 : How To Find The Length Of The Side Of A 45/45/90 Right Isosceles Triangle

If the hypotenuse of a right isosceles triangle is , what is the length of a side of the triangle?

Possible Answers:

Correct answer:

Explanation:

A right isosceles triangle is also a  triangle.

13

To find the length of a side, we will need to use the Pythagorean Theorem:

Since this is an isosceles triangle, 

The Pythagorean Theorem can then be rewritten as the following:

Since we are trying to find the length of a side of this triangle, solve for .

Simplify.

Multiply the fraction by one in the form of .

Solve.

Now, substitute in the length of the hypotenuse in for  to solve for the side of the triangle in the question.

Simplify.

Reduce.

Example Question #7 : How To Find The Length Of The Side Of A 45/45/90 Right Isosceles Triangle

If the hypotenuse of a right isosceles triangle is , what is the length of a side of this triangle?

Possible Answers:

Correct answer:

Explanation:

A right isosceles triangle is also a  triangle.

13

To find the length of a side, we will need to use the Pythagorean Theorem:

Since this is an isosceles triangle, 

The Pythagorean Theorem can then be rewritten as the following:

Since we are trying to find the length of a side of this triangle, solve for .

Simplify.

Multiply the fraction by one in the form of .

Solve.

Now, substitute in the length of the hypotenuse in for  to solve for the side of the triangle in the question.

Simplify.

Reduce.

Example Question #4 : How To Find The Length Of The Side Of A 45/45/90 Right Isosceles Triangle

If the hypotenuse of a right isosceles triangle is , what is the length of a side of this triangle?

Possible Answers:

Correct answer:

Explanation:

A right isosceles triangle is also a  triangle.

13

To find the length of a side, we will need to use the Pythagorean Theorem:

Since this is an isosceles triangle, 

The Pythagorean Theorem can then be rewritten as the following:

Since we are trying to find the length of a side of this triangle, solve for .

Simplify.

Multiply the fraction by one in the form of .

Solve.

Now, substitute in the length of the hypotenuse in for  to solve for the side of the triangle in the question.

Simplify.

Reduce.

Example Question #171 : Triangles

If the hypotenuse of a right isosceles triangle is , what is the length of a side of the triangle?

Possible Answers:

Correct answer:

Explanation:

A right isosceles triangle is also a  triangle.

13

To find the length of a side, we will need to use the Pythagorean Theorem:

Since this is an isosceles triangle, 

The Pythagorean Theorem can then be rewritten as the following:

Since we are trying to find the length of a side of this triangle, solve for .

Simplify.

Multiply the fraction by one in the form of .

Solve.

Now, substitute in the length of the hypotenuse in for  to solve for the side of the triangle in the question.

Simplify.

Reduce.

Example Question #172 : Triangles

If the hypotenuse of a right isosceles triangle is , what is the length of a side of the triangle?

Possible Answers:

Correct answer:

Explanation:

A right isosceles triangle is also a  triangle.

13

To find the length of a side, we will need to use the Pythagorean Theorem:

Since this is an isosceles triangle, 

The Pythagorean Theorem can then be rewritten as the following:

Since we are trying to find the length of a side of this triangle, solve for .

Simplify.

Multiply the fraction by one in the form of .

Solve.

Now, substitute in the length of the hypotenuse in for  to solve for the side of the triangle in the question.

Simplify.

Reduce.

Example Question #173 : Triangles

If the hypotenuse of a right isosceles triangle is , what is the length of a side of the triangle?

Possible Answers:

Correct answer:

Explanation:

A right isosceles triangle is also a  triangle.

13

To find the length of a side, we will need to use the Pythagorean Theorem:

Since this is an isosceles triangle, 

The Pythagorean Theorem can then be rewritten as the following:

Since we are trying to find the length of a side of this triangle, solve for .

Simplify.

Multiply the fraction by one in the form of .

Solve.

Now, substitute in the length of the hypotenuse in for  to solve for the side of the triangle in the question.

Simplify.

Reduce.

Example Question #174 : Triangles

If the hypotenuse of a right isosceles triangle is , what is the length of one side of the triangle?

Possible Answers:

Correct answer:

Explanation:

A right isosceles triangle is also a  triangle.

13

To find the length of a side, we will need to use the Pythagorean Theorem:

Since this is an isosceles triangle, 

The Pythagorean Theorem can then be rewritten as the following:

Since we are trying to find the length of a side of this triangle, solve for .

Simplify.

Multiply the fraction by one in the form of .

Solve.

Now, substitute in the length of the hypotenuse in for  to solve for the side of the triangle in the question.

Simplify.

Reduce.

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