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## Class 9 (Assamese)

### Course: Class 9 (Assamese)>Unit 9

Lesson 1: Area of a parallelogram

# Area of parallelogram proof

Learn to use the formula, A=bh to find the area of parallelograms. Created by Sal Khan.

## Want to join the conversation?

• What is SSS?
• SSS is basically Side-Side-Side used to explain how you tell this is a congruent triangle.
There is also S.A.S., A.S.A., R.H.S., A.A.S. too.
S.A.S.: Side-Angle-Side
A.S.A.: Angle-Side-Angle
R.H.S.: Right-angle-Hypotenuse-Side
A.A.S.: Angle-Angle-Side
SAS (Side-Angle-Side): If two pairs of sides of two triangles are equal in length, and the included angles are equal in measurement, then the triangles are congruent.
SSS (Side-Side-Side): If three pairs of sides of two triangles are equal in length, then the triangles are congruent.
ASA (Angle-Side-Angle): If two pairs of angles of two triangles are equal in measurement, and the included sides are equal in length, then the triangles are congruent.
The ASA Postulate was contributed by Thales of Miletus (Greek). In most systems of axioms, the three criteria—SAS, SSS and ASA—are established as theorems. In the School Mathematics Study Group system SAS is taken as one (#15) of 22 postulates.
AAS (Angle-Angle-Side): If two pairs of angles of two triangles are equal in measurement, and a pair of corresponding non-included sides are equal in length, then the triangles are congruent. (In British usage, ASA and AAS are usually combined into a single condition AAcorrS - any two angles and a corresponding side.)
RHS (Right-angle-Hypotenuse-Side): If two right-angled triangles have their hypotenuses equal in length, and a pair of shorter sides are equal in length, then the triangles are congruent. Also known as LH (Hypotenuse-Leg).
• How do you find the height of a parallelogram when given an interior angle measure, and the length of the sides? I was not given the area of the parallelogram.
• Let k be the length of the side that is not the base.
Let h be the height
Let θ be the angle between the base and the side k.
h = k sin θ
Let b be the length of the base:
Area = k b sin θ
• At , Sal said that the area of the parallelogram is 5x6, whereas before, following the previously spoken format it would be 2x5x6. Is this right?
• he explained how 2 x 1/2 is equal to 1. This means, the 2 triangles are eliminated and beomes one object to be answered as base x height
(1 vote)
• Sometimes the height is not given, how are we supposed to find that? I dont get it Please give the simplest way of doing so.
• If the base and the area are given, use algebra to solve for the height using the formula area is equal to base times height (a = b x h). If the area isn't given but the base is given, there might be a dashed line (the height) perpendicular to the base. The length of the side adjacent to the base, and the measure from the dashed line to the end of the base, should both be given in this case in which neither the height or area are given. Use the Pythagorean Theorem (a^2 + b^2 = c^2) to solve for the long side (the height). Sorry if this was worded weirdly or was otherwise unhelpful.
• What is SSS?
• That means side side side. It is a congruence postulate.
• What's the difference between finding the area of a parallelogram vs a rhombas?
• A rhombus is a type of parallelogram, thus you can find the area of a rhombus by any means that would work for a parallelogram.

However, finding the area of a rhombus can be easier, depending on what you know. Here is a link that shows the three main ways of finding the area of a rhombus:
http://www.mathopenref.com/rhombusarea.html
• technically, wouldn't BH work as well?
• I have a very simple way to solve it . multiplication. simply multiply the numbers given to you and boom, you have the area of the parallelogram .
• CED is an equilateral triangle in the square ABCD. The diagonal DB intersects equilateral triangle at F. find the value of x . the triangle formed by intersecting of CED by diagonal DB is x
• What parameter of x are you trying to solve for? Length, angle, area?
• What does Congruent mean?
(1 vote)
• Congruent means that 2 or more shapes look exactly the same in shape and size.
• what will happen if there was no given height or base?
(1 vote)
• Khan Academy is a non-profit educational organization created in 2006 by educator Salman Khan to provide "a free, world-class education for anyone, anywhere". The organization produces micro lectures in the form of YouTube videos. Wikipedia
Founder: Salman Khan
Founded: September 2006
Assets: 1.623 million USD (2010)
Revenue: 15.8 million USD (2012)
CEO: Salman Khan
Nonprofit category: Education
(1 vote)