Advanced Geometry : Rhombuses

Study concepts, example questions & explanations for Advanced Geometry

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Example Questions

Example Question #142 : Quadrilaterals

 

 

 

Find the lengths of the two diagonals, the longer diagonal is , the shorter diagonal is .

Varsity1

Possible Answers:

Correct answer:

Explanation:

1) All sides of a rhombus are congruent.

2) Because all sides of a rhombus are congruent, the expressions of the side lengths can be set equal to each other.  The resulting equation is then solved,

3) Because the sides of a rhombus are congruent,  can be substituted into either  or  to find the length of a side,

, or, .

4) Each of the composing triangles are right triangles, so then  is the length of the hypotenuse for each triangle.

5) .

6) The standard  right triangle has a hypotenuse length equal to .

7) The hypotenuse of a standard  right triangle is being multiplied by .  

The result is , so then  is the scale factor for the triangle side lengths.

8) For the standard  right triangle, the other two side lengths are  and , so then the height of the triangle from step 7) has a height of , and the base length is .

9) The base of the triangle from step 7) is 

,

and the height is 

.

10) Diagonal 

,

and diagonal 

.

 

 

 

Example Question #11 : How To Find The Length Of The Diagonal Of A Rhombus

Screen_shot_2015-03-06_at_3.16.41_pm

What is the second diagonal for the above rhombus?

Possible Answers:

Correct answer:

Explanation:

Because a rhombus has vertical and horizontal symmetry, it can be broken into four congruent triangles, each with a hypotenuse of 13 and a base of 5 (half the given diagonal).

The Pythagorean Theorem

 will yield,

  for the height of the triangles.

The greater diagonal is twice the height of the triangles therefore, the greater diagonal becomes:

Example Question #141 : Quadrilaterals

 is rhombus with side lengths in meters.  and . What is the length, in meters, of ?

Rhombus_1

Possible Answers:

30

24

15

5

12

Correct answer:

24

Explanation:

A rhombus is a quadrilateral with four sides of equal length. Rhombuses have diagonals that bisect each other at right angles.

Rhombus_2

Thus, we can consider the right triangle  to find the length of diagonal . From the given information, each of the sides of the rhombus measures  meters and .

Because the diagonals bisect each other, we know:

Using the Pythagorean theorem,

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