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22. (l2) identify the converse of the following statement, and determin…

Question

  1. (l2) identify the converse of the following statement, and determine whether it is true or false

if a triangle is equiangular, then it has three angles with equal measures.
a. if a triangle has less than three angles with equal measures, then it is equiangular; false
b. if a triangle has three angles with equal measures, then it is equiangular; true
c. if a triangle has three angles with equal measures, then it is equiangular; false
d. if a triangle has less than three angles with equal measures, then it is equiangular; true
e. if three angles of a triangle are measured, then it is an equiangular triangle; false

  1. select the correct proof from the options listed.

given: \\( \triangle j l m \\) is equilateral; \\( z \\) is the midpoint of \\( \overline{j m} \\)
prove: \\( \triangle j z l \cong \triangle m z l \\)
a.
\

$$\begin{tabular}{l|l} statements & reasons \\\\ \\hline 1. \\( \\triangle j l m \\) is equilateral. & 1. given \\\\ 2. \\( \\overline{j l} \\cong \\overline{m l} \\) & 2. definition of an equilateral triangle \\\\ 3. \\( z \\) is the midpoint of \\( \\overline{j m} \\). & 3. given \\\\ 4. \\( \\overline{j z} \\cong \\overline{m z} \\) & 4. definition of a midpoint \\\\ 5. \\( \\overline{l z} \\cong \\overline{l z} \\) & 5. reflexive property \\\\ 6. \\( \\triangle j z l \\cong \\triangle m z l \\) & 6. side-side-side postulate \\\\ \\end{tabular}$$

b.
\

$$\begin{tabular}{l|l} statements & reasons \\\\ \\hline 1. \\( \\triangle j l m \\) is equilateral. & 1. given \\\\ 2. \\( \\overline{j l} \\cong \\overline{l z} \\) & 2. definition of an equilateral triangle \\\\ 3. \\( z \\) is the midpoint of \\( \\overline{j m} \\). & 3. given \\\\ 4. \\( \\overline{j z} \\cong \\overline{m z} \\) & 4. definition of parallel lines \\\\ 5. \\( \\overline{l z} \\cong \\overline{l z} \\) & 5. substitution property \\\\ 6. \\( \\triangle j z l \\cong \\triangle m z l \\) & 6. angle-side-angle postulate \\\\ \\end{tabular}$$

c.
\

$$\begin{tabular}{l|l} statements & reasons \\\\ \\hline 1. \\( \\triangle j l m \\) is equilateral. & 1. given \\\\ 2. \\( z \\) is the midpoint of \\( \\overline{j m} \\). & 2. given \\\\ 3. \\( \\overline{l z} \\perp \\overline{j m} \\) & 3. definition of an equilateral triangle \\\\ 4. \\( \\overline{j z} \\cong \\overline{m z} \\) & 4. definition of a midpoint \\\\ 5. \\( \\overline{l z} \\cong \\overline{l z} \\) & 5. reflexive property \\\\ 6. \\( \\triangle j z l \\cong \\triangle m z l \\) & 6. side-angle-side postulate \\\\ \\end{tabular}$$

d.
\

$$\begin{tabular}{l|l} statements & reasons \\\\ \\hline 1. \\( \\triangle j l m \\) is equilateral. & 1. given \\\\ 2. \\( \\angle j l z \\cong \\angle m l z \\) & 2. congruent angles are created by two lines cut by \\\\ & a transversal. \\\\ 3. \\( \\overline{l z} \\perp \\overline{j m} \\) & 3. definition of perpendicular lines \\\\ 4. \\( \\overline{l z} \\cong \\overline{l z} \\) & 4. same line \\\\ 5. \\( \\triangle j z l \\cong \\triangle m z l \\) & 5. angle-side-angle postulate \\\\ \\end{tabular}$$

Explanation:

22.
Brief Explanations

For a conditional statement “If \(p\), then \(q\)” (\(p
ightarrow q\)), the converse is “If \(q\), then \(p\)” (\(q
ightarrow p\)).
In the statement “If a triangle is equiangular (\(p\)), then it has three angles with equal measures (\(q\))”, the converse is “If a triangle has three angles with equal measures (\(q\)), then it is equiangular (\(p\))”.
By the definition of an equiangular triangle (a triangle with all angles equal), the converse is a true statement.

Brief Explanations
  • Option A:
  • Since \(\triangle JLM\) is equilateral, by the definition of an equilateral triangle, \(JL = ML\) (so \(\overline{JL}\cong\overline{ML}\)).
  • \(Z\) is the mid - point of \(\overline{JM}\), so by the definition of a mid - point, \(JZ = MZ\) (so \(\overline{JZ}\cong\overline{MZ}\)).
  • \(\overline{LZ}\cong\overline{LZ}\) by the reflexive property (\(a = a\) for any geometric segment \(a\)).
  • Then, by the Side - Side - Side (SSS) postulate (\(\triangle ABC\cong\triangle DEF\) if \(AB = DE\), \(BC=EF\), and \(AC = DF\)), \(\triangle JZL\cong\triangle MZL\) since \(JL = ML\), \(JZ = MZ\), and \(LZ = LZ\).
  • Option B:
  • In an equilateral triangle \(\triangle JLM\), \(JL

eq LZ\) (the side of an equilateral triangle is not equal to a segment from a vertex to a mid - point of a non - adjacent side). Also, the reason for \(\overline{JZ}\cong\overline{MZ}\) should be the definition of a mid - point, not parallel lines. And the postulate used is incorrect as we have three pairs of sides, not angles - sides - angles.

  • Option C:
  • Just because \(Z\) is the mid - point of \(\overline{JM}\) in an equilateral triangle \(\triangle JLM\), we cannot directly say \(\overline{LZ}\perp\overline{JM}\) (this is a property of an isosceles triangle's median, but we need to prove it first. Also, the postulate used is incorrect as we have three pairs of sides for SSS, not side - angle - side).
  • Option D:
  • \(\angle JL Z\cong\angle MLZ\) is not a given property (we need to prove it using the SSS congruence of triangles, not assume it from some transversal property). Also, \(\overline{LZ}\perp\overline{JM}\) is not established, and the steps and reasons are jumbled.

Answer:

B. If a triangle has three angles with equal measures, then it is equiangular; true

23.