Find AREA of ABC

[giaminhsj]

5th grade problem
right triangle ABC with BC= 24, the line from mid point of AB parallel to AC and cut BC at D. Area of MBD = 120, find the Area of ABC

 

[chrisr]

AC is 24.

What are your calculations on it ?

If you include a point E, such that BE is parallel to AC and of equal length,
also AB is parallel to CE,
then you have a rectangle ABEC.
Now, how much of ABEC is BMD ?

Or draw a line straight down from D to AC
and draw a line from D to A.
What's the story with the 4 resulting triangles ?

edited out a typo.

 

[Mrspi]

5th grade problem
right triangle ABC with BC= 24, the line from mid point of AB parallel to AC and cut BC at D. Area of MBD = 120, find the Area of ABC

You say BC = 24, but your diagram shows AC = 24. Which is it? It DOES make a difference!

 

[Deleted member 4993]

5th grade problem
right triangle ABC with BC= 24, the line from mid point of AB parallel to AC and cut BC at D. Area of MBD = 120, find the Area of ABC

MD = 1/2 * AC

BM = 1/2 * AB

Now you can find the ratio of (the areas) the triangles MBD and ABC.

Please share your work with us, indicating exactly where you are stuck - so that we know where to begin to help you.

 

[Aladdin]

Can't we say :

AC=2MD

AB=2MB

BC=2BD

Area of larger triangle ABC is 2(2)(area of BMD)

 

[soroban]

Hello, giaminhsj!

Here is an "eyebnall" solution . . .

  B o
    |   *
    | 120   *
    |           *
  M o - - - - - - - o D
    |   *     120   |   *
    | 120   *       | 120   *
    |           *   |           *
  A o - - - - - - - o - - - - - - - o C