Math Problem Statement

Solve the geometry problems: 17. If K is the incenter of ΔEFG, find x and each angle measure. 18. If P is the centroid of ΔJKL, find each measure given segment details.

Solution

Let's solve the problems in the image step by step.


Problem 17

If KK is the incenter of EFG\triangle EFG:

  • KK is the point where the angle bisectors meet.
  • The angle measures at EFG\triangle EFG must add up to 180180^\circ.

We have the given angles:

  1. KEJ=18x23\angle KEJ = 18x - 23
  2. JEG=7x1\angle JEG = 7x - 1
  3. EFG=47\angle EFG = 47^\circ.

Solution: The sum of all angles in EFG\triangle EFG is: (18x23)+(7x1)+47=180(18x - 23) + (7x - 1) + 47 = 180

Simplify: 25x+23=18025x + 23 = 180

Solve for xx: 25x=157    x=6.28(approximately).25x = 157 \quad \implies \quad x = 6.28 \, \text{(approximately)}.

Now, find each angle measure:

  1. KEJ=18x23=18(6.28)23=113.0423=90.04\angle KEJ = 18x - 23 = 18(6.28) - 23 = 113.04 - 23 = 90.04^\circ.
  2. JEG=7x1=7(6.28)1=43.96\angle JEG = 7x - 1 = 7(6.28) - 1 = 43.96^\circ.
  3. EFG=47\angle EFG = 47^\circ.
  4. FGE=180(KEJ+JEG)=180(90.04+43.96)=46\angle FGE = 180 - (\angle KEJ + \angle JEG) = 180 - (90.04 + 43.96) = 46^\circ.

Problem 18

If PP is the centroid of JKL\triangle JKL:

  • A centroid divides each median into a 2:12:1 ratio.

Given:

  1. PN=5PN = 5,
  2. LM=33LM = 33,
  3. KP=16KP = 16,
  4. NL=13NL = 13.

Solution:

  1. PMPM: Since PP divides LMLM into a 2:12:1 ratio: PM=23×33=22PM = \frac{2}{3} \times 33 = 22

  2. PLPL: Since PP divides KLKL into a 2:12:1 ratio: PL=23×KP=23×16=10.67PL = \frac{2}{3} \times KP = \frac{2}{3} \times 16 = 10.67

  3. POPO: Since PP divides NLNL into a 2:12:1 ratio: PO=23×13=8.67PO = \frac{2}{3} \times 13 = 8.67

  4. JPJP: From JP=PN+POJP = PN + PO: JP=5+8.67=13.67JP = 5 + 8.67 = 13.67

  5. JNJN: Sum JP+PNJP + PN: JN=13.67+5=18.67JN = 13.67 + 5 = 18.67

  6. KLKL: Total segment KL=3×KP/2KL = 3 \times KP / 2: KL=3×16/2=24KL = 3 \times 16 / 2 = 24


Final Answers:

Problem 17:

  • x=6.28x = 6.28
  • mKEJ=90.04m\angle KEJ = 90.04^\circ
  • mEFG=47m\angle EFG = 47^\circ
  • mFGE=46m\angle FGE = 46^\circ
  • mKGJ=m\angle KGJ = (can be calculated based on geometry, assuming symmetry).

Problem 18:

  • PM=22PM = 22
  • PL=10.67PL = 10.67
  • PO=8.67PO = 8.67
  • JP=13.67JP = 13.67
  • JN=18.67JN = 18.67
  • KL=24KL = 24

Do you need further clarification or detailed explanations for any part of this solution?

Here are 5 additional questions to expand your understanding:

  1. How can the centroid formula be derived geometrically?
  2. What are the properties of an incenter in a triangle?
  3. Why does the sum of angles in a triangle always equal 180180^\circ?
  4. How do you confirm the 2:12:1 ratio property of the centroid?
  5. How can angle bisectors help in solving triangle properties?

Tip: Always double-check your calculations, especially when working with angle measures and triangle properties!

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Math Problem Analysis

Mathematical Concepts

Geometry
Triangles
Incenter
Centroid

Formulas

Sum of angles in a triangle = 180°
Centroid divides a median in a 2:1 ratio
Basic algebraic equations to solve for x

Theorems

Incenter is the intersection of angle bisectors
Centroid divides medians in a 2:1 ratio

Suitable Grade Level

Grades 9-11