Question

1. list all the right angles. why are they right angles? 13. list all the acute angles. why are they acute angles? 14. list all the straight angles. why are they straight angles? 15. list all the obtuse angles. why are they obtuse angles?

Explanation:

Step1: Recall angle - type definitions

A right - angle measures 90 degrees, an acute angle measures less than 90 degrees, a straight angle measures 180 degrees, and an obtuse angle measures more than 90 degrees but less than 180 degrees.

Step2: Identify right angles

$\angle{JKN}$ is a right angle because it is marked with a right - angle symbol.

Step3: Identify acute angles

$\angle{MKJ}$, $\angle{MKL}$, $\angle{NKL}$, $\angle{NKJ}$, $\angle{OKJ}$, $\angle{OKL}$ are acute angles as they are smaller than 90 - degree angles.

Step4: Identify straight angles

$\angle{JKL}$ is a straight angle as it is a 180 - degree angle formed by the straight line JL with K as a point on it.

Step5: Identify obtuse angles

$\angle{MKL}$ (if considering the non - acute part of the angle formed by MK and KL in a non - acute sense) is an obtuse angle as it is greater than 90 degrees and less than 180 degrees.

Answer:

1. Right angles: $\angle{JKN}$; Reason: Marked with a right - angle symbol, measures 90 degrees.
2. Acute angles: $\angle{MKJ}$, $\angle{MKL}$, $\angle{NKL}$, $\angle{NKJ}$, $\angle{OKJ}$, $\angle{OKL}$; Reason: Measure less than 90 degrees.
3. Straight angle: $\angle{JKL}$; Reason: Forms a straight line, measures 180 degrees.
4. Obtuse angle: $\angle{MKL}$ (non - acute part); Reason: Measures more than 90 degrees and less than 180 degrees.