What is the area of the quadrilateral?

  • Context: MHB 
  • Thread starter Thread starter Monokonos
  • Start date Start date
  • Tags Tags
    Area
Click For Summary
SUMMARY

The area of the quadrilateral KLMN, inscribed in a circle with center O, is calculated by dividing it into two triangles: KLM and KNM. The lengths provided are KL = 18 and LM = 24, leading to the area of triangle KLM being 216 square units. The diameter KM measures 30 units, making triangle KNM isosceles with an area of 225 square units. Therefore, the total area of quadrilateral KLMN is 441 square units.

PREREQUISITES
  • Understanding of basic geometry concepts, specifically quadrilaterals and triangles.
  • Knowledge of the Pythagorean theorem for calculating lengths in right triangles.
  • Familiarity with properties of inscribed angles and semicircles.
  • Ability to calculate the area of triangles using base and height.
NEXT STEPS
  • Study the properties of cyclic quadrilaterals and their area calculations.
  • Learn advanced triangle area formulas, including Heron's formula.
  • Explore geometric constructions involving circles and inscribed figures.
  • Investigate the relationship between diameters and angles in semicircles.
USEFUL FOR

Students studying geometry, educators teaching geometric principles, and anyone interested in solving problems related to quadrilaterals and circle properties.

Monokonos
Messages
1
Reaction score
0
View attachment 7882
https://gyazo.com/55afe69c0f00bff85a3a9c53bd353b42

Sorry for the really poorly drawn and lit picture...

Basically this quadrilateral is drawn inside a circle whose middle point is O. Here is the info I was given

KL = 18
LM = 24
KN = NM

What I need to find out is the area of KLMN.

What I did there split the quadrilateral into 2 with a diameter. I found out the length of that with the pythagorean theorem. It was 30. So logically the area of that triangle is 24x18/2 = 225.

But how do I find out the volume of the second triangle? I know it's really simple but I just can't figure it out...
 

Attachments

  • 55afe69c0f00bff85a3a9c53bd353b42.jpg
    55afe69c0f00bff85a3a9c53bd353b42.jpg
    55.7 KB · Views: 158
Last edited by a moderator:
Mathematics news on Phys.org
If KM is a diameter, then triangle KNM is isosceles with base KM = 30 and height ON = 15 $\implies$ area of triangle KNM is 225.

triangle KLM is inscribed in a semicircle, therefore angle L is 90 degrees ...

area of triangle KLM is 216
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
1K
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 11 ·
Replies
11
Views
4K
  • · Replies 2 ·
Replies
2
Views
4K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K