ISEE Upper Level Quantitative : ISEE Upper Level (grades 9-12) Quantitative Reasoning

Study concepts, example questions & explanations for ISEE Upper Level Quantitative

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Example Questions

Example Question #81 : Plane Geometry

Which is the greater quantity? 

(a) The measure of an angle complementary to a \displaystyle 55 ^{\circ } angle

(b) The measure of an angle supplementary to a \displaystyle 135 ^{\circ } angle

Possible Answers:

(a) is greater

It is impossible to tell from the information given

(a) and (b) are equal

(b) is greater

Correct answer:

(b) is greater

Explanation:

Supplementary angles and complementary angles have measures totaling \displaystyle 180^{\circ } and \displaystyle 90^{\circ }, respectively.

(a) The measure of an angle complementary to a \displaystyle 55 ^{\circ } angle is \displaystyle 90^{\circ } - 55^{\circ } = 35^{\circ }

(b) The measure of an angle supplementary to a \displaystyle 135 ^{\circ } angle is \displaystyle 180^{\circ } - 135 ^{\circ } = 45^{\circ }

This makes (b) greater.

Example Question #1 : Lines

\displaystyle \angle 1 and \displaystyle \angle 2 are complementary; \displaystyle m \angle 1 =2 m \angle 2 - 50.

Which is the greater quantity?

(A) \displaystyle m \angle 1

(B) \displaystyle m \angle 2

Possible Answers:

(B) is greater 

It is impossible to determine which is greater from the information given

(A) is greater

(A) and (B) are equal

Correct answer:

(B) is greater 

Explanation:

Two angles are complementary if their degree measures total 90. Therefore, 

\displaystyle m \angle 1 + m \angle 2 = 90

Since \displaystyle m \angle 1 =2 m \angle 2 - 50, we can substitute, and we can solve for \displaystyle m\angle2:

\displaystyle (2 m \angle 2 - 50)+ m \angle 2 = 90

\displaystyle 3 m \angle 2 - 50 = 90

\displaystyle 3 m \angle 2 - 50 + 50 = 90 + 50

\displaystyle 3 m \angle 2 = 140

\displaystyle 3 m \angle 2 \div 3 = 140 \div 3

\displaystyle m \angle 2 = 46 \frac{2}{3}

\displaystyle m \angle 1 = 90 - m \angle 2 = 90 - 46 \frac{2}{3} = 43 \frac{1}{3}

\displaystyle m \angle 2 > m \angle 1, making (B) the greater quantity.

Example Question #2 : Lines

Untitled

Note: diagram is not drawn to scale

Refer to the above diagram. If  \displaystyle m \angle1 = m \angle 2 + 30, what is \displaystyle m \angle1 ?

Possible Answers:

\displaystyle 105 ^{\circ }

\displaystyle 110 ^{\circ }

\displaystyle 115 ^{\circ }

\displaystyle 120 ^{\circ }

\displaystyle 100 ^{\circ }

Correct answer:

\displaystyle 105 ^{\circ }

Explanation:

\displaystyle \angle 1 and \displaystyle \angle 2 form a linear pair, so 

\displaystyle m \angle1 + m \angle 2 = 180

Since \displaystyle m \angle1 = m \angle 2 + 30, this can be rewritten as

\displaystyle m \angle1 - 30 = m \angle 2, and the first equation can be rewritten as:

\displaystyle m \angle1 + m \angle1 - 30 = 180

\displaystyle 2 m \angle1 - 30 = 180

\displaystyle 2 m \angle1 - 30 + 30 = 180 + 30

\displaystyle 2 m \angle1 = 210

\displaystyle 2 m \angle1 \div 2 = 210 \div 2

\displaystyle m \angle1 = 105

Example Question #1 : Lines

Untitled

Note: Figure NOT drawn to scale.

Which of the following pairs of numbers could give the measures of \displaystyle \angle 1 and \displaystyle \angle 2 ?

Possible Answers:

\displaystyle 64^{\circ }, 36^{\circ }

None of the pairs given in the other choices is correct.

\displaystyle 55^{\circ }, 35^{\circ }

\displaystyle 124^{\circ }, 76^{\circ }

\displaystyle 112^{\circ }, 68^{\circ }

Correct answer:

\displaystyle 112^{\circ }, 68^{\circ }

Explanation:

The two angles form a linear pair and therefore their measures total \displaystyle 180^{\circ }. We check all of the pairs for this sum.

\displaystyle 55+35 = 90

\displaystyle 64+ 36 = 100

\displaystyle 112+ 68 = 180

\displaystyle 124+76 = 200

The correct pair is \displaystyle 112^{\circ }, 68^{\circ }.

Example Question #5 : Lines

Triangle

Note: Figure NOT drawn to scale.

Refer to the above diagram. Which of the following triples could refer to the measures of \displaystyle \angle 1\displaystyle \angle 2, and \displaystyle \angle 3 ?

Possible Answers:

\displaystyle 42 ^{\circ }, 72 ^{\circ }, 114 ^{\circ }

\displaystyle 30 ^{\circ }, 80 ^{\circ }, 110 ^{\circ }

All of the other responses are correct.

\displaystyle 56 ^{\circ }, 86 ^{\circ }, 142 ^{\circ }

\displaystyle 25 ^{\circ }, 88 ^{\circ }, 113 ^{\circ }

Correct answer:

All of the other responses are correct.

Explanation:

The measure of an exterior angle of a triangle, which here is \displaystyle \angle 3, is the sum of the measures of its remote interior angles, which here are  \displaystyle \angle 1 and \displaystyle \angle 2. Therefore, we are looking for the sum of the first two angle measures to be equal to the third.

\displaystyle 42 ^{\circ }+ 72 ^{\circ } = 114 ^{\circ }

\displaystyle 30 ^{\circ } + 80 ^{\circ } = 110 ^{\circ }

\displaystyle 56 ^{\circ } + 86 ^{\circ } = 142 ^{\circ }

\displaystyle 25 ^{\circ }+ 88 ^{\circ } = 113 ^{\circ }

All four triples satisfy this condition.

Example Question #3 : Lines

Untitled

Note: figure NOT drawn to scale

The degree measure of \displaystyle \angle 1 is five degrees greater than twice that of \displaystyle \angle 2. Which is the greater quantity?

(A) \displaystyle m \angle 2

(B) \displaystyle 55^{\circ }

Possible Answers:

(A) is greater

(A) and (B) are equal

(B) is greater

It is impossible to determine which is greater from the information given

Correct answer:

(A) is greater

Explanation:

The degree measure of \displaystyle \angle 1 is five degrees greater than twice that of \displaystyle \angle 2 - that is, 

\displaystyle m \angle 1 = 2 m \angle 2 + 5

Since \displaystyle \angle 1 and \displaystyle \angle 2 form a linear pair, 

 \displaystyle m\angle1 + m\angle 2 = 180, and by substitution, 

\displaystyle ( 2 m \angle 2 + 5)+ m\angle 2 = 180

\displaystyle 3 m \angle 2 + 5 = 180

\displaystyle 3 m \angle 2 + 5 - 5 = 180 - 5

\displaystyle 3 m \angle 2 = 175

\displaystyle 3 m \angle 2 \div 3 = 175\div 3

\displaystyle m \angle 2 = 58 \frac{1}{3} > 55

This makes (A) greater.

Example Question #6 : Lines

Untitled

Note: Figure NOT drawn to scale

\displaystyle m\angle 2 = 48 ^{\circ } . What is \displaystyle m \angle 1 ?

Possible Answers:

\displaystyle m \angle 1 = 122^{\circ }

\displaystyle m \angle 1 = 142^{\circ }

\displaystyle m \angle 1 = 112^{\circ }

\displaystyle m \angle 1 = 102^{\circ }

\displaystyle m \angle 1 = 132^{\circ }

Correct answer:

\displaystyle m \angle 1 = 132^{\circ }

Explanation:

\displaystyle \angle 1 and \displaystyle \angle 2 form a linear pair and therfore, the the sum of their degree measures is \displaystyle 180^{\circ }

\displaystyle m\angle 1 + m\angle 2 = 180^{\circ }

\displaystyle m\angle 1 + 48 ^{\circ } = 180^{\circ }

\displaystyle m\angle 1 + 48 ^{\circ } - 48 ^{\circ } = 180^{\circ } - 48 ^{\circ }

\displaystyle m\angle 1 = 132 ^{\circ }

Example Question #2 : Lines

Triangle

Note: Figure NOT drawn to scale.

\displaystyle m \angle 3 = 125 ^{\circ }

\displaystyle 3 m \angle 1 = 2 m \angle 2

Evaluate \displaystyle m \angle 1.

Possible Answers:

\displaystyle m \angle 1 = 25^{\circ }

\displaystyle m \angle 1 = 60 ^{\circ }

\displaystyle m \angle 1 = 35 ^{\circ }

\displaystyle m \angle 1 = 50 ^{\circ }

\displaystyle m \angle 1 = 75 ^{\circ }

Correct answer:

\displaystyle m \angle 1 = 50 ^{\circ }

Explanation:

\displaystyle 3 m \angle 1 = 2 m \angle 2, so 

\displaystyle 3 \left (m \angle 1 \right ) \div 2 = 2\left ( m \angle 2 \right )\div 2

\displaystyle \frac{3}{2} m \angle 1 = m \angle 2

The measure of an exterior angle of a triangle, which here is \displaystyle \angle 3, is the sum of the measures of its remote interior angles, which here are  \displaystyle \angle 1 and \displaystyle \angle 2.

\displaystyle m \angle 1 + m \angle 2 = m \angle 3

\displaystyle m \angle 1 + \frac{3}{2} m \angle 1 = 125 ^{\circ }

\displaystyle \frac{5}{2} m \angle 1 = 125 ^{\circ }

\displaystyle \frac{2}{5} \cdot \frac{5}{2} m \angle 1 = \frac{2}{5} \cdot 125 ^{\circ }

\displaystyle m \angle 1 =50 ^{\circ }

 

Example Question #81 : Plane Geometry

What is the slope of a line that passes through points \displaystyle (10,25) and \displaystyle (5, 10)?

 

Possible Answers:

\displaystyle \frac{1}{3}

\displaystyle -\frac{1}{3}

\displaystyle -3

\displaystyle 3

Correct answer:

\displaystyle 3

Explanation:

The equation for solving for the slope of a line is \displaystyle m=\frac{y2-y1}{x2-x1}

Thus, if \displaystyle (x1,y1)=(10, 25) and \displaystyle (x2,y2)=(5,10), then:

\displaystyle m=\frac{25-10}{10-5}=\frac{15}{5}=3

Example Question #81 : Plane Geometry

What is the slope of a line that passes through points \displaystyle (4.5,2.5) and \displaystyle (3.5, 6.5)?

 

Possible Answers:

\displaystyle 4

\displaystyle -4

\displaystyle \frac{1}{4}

\displaystyle -\frac{1}{4}

Correct answer:

\displaystyle -4

Explanation:

The equation for solving for the slope of a line is \displaystyle m=\frac{y2-y1}{x2-x1}

Thus, if \displaystyle (x1,y1)=(4.5, 2.5) and \displaystyle (x2,y2)=(3.5,6.5), then:

\displaystyle m=\frac{6.5-2.5}{3.5-4.5}=\frac{4}{-1}=-4

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