ISEE Middle Level Quantitative : ISEE Middle Level (grades 7-8) Quantitative Reasoning

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

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Example Questions

Example Question #125 : Rectangles

Joe has a piece of wallpaper that is \(\displaystyle 5ft\) by \(\displaystyle 3ft\). How much of a wall can be covered by this piece of wallpaper?

 

Possible Answers:

\(\displaystyle 16ft^2\)

\(\displaystyle 14ft^2\)

\(\displaystyle 17ft^2\)

\(\displaystyle 13ft^2\)

\(\displaystyle 15ft^2\)

Correct answer:

\(\displaystyle 15ft^2\)

Explanation:

This problem asks us to calculate the amount of space that the wallpaper will cover. The amount of space that something covers can be described as its area. In this case area is calculated by using the formula \(\displaystyle A=l \times w\)

\(\displaystyle A=5\times3\)

\(\displaystyle A=15ft^2\)

Example Question #126 : Rectangles

Joe has a piece of wallpaper that is \(\displaystyle 9ft\) by \(\displaystyle 7ft\). How much of a wall can be covered by this piece of wallpaper?

 

Possible Answers:

\(\displaystyle 66ft^2\)

\(\displaystyle 63ft^2\)

\(\displaystyle 64ft^2\)

\(\displaystyle 65ft^2\)

\(\displaystyle 67ft^2\)

Correct answer:

\(\displaystyle 63ft^2\)

Explanation:

This problem asks us to calculate the amount of space that the wallpaper will cover. The amount of space that something covers can be described as its area. In this case area is calculated by using the formula \(\displaystyle A=l \times w\)

\(\displaystyle A=9\times7\)

\(\displaystyle A=63ft^2\)

Example Question #1 : Trapezoid

Square c

Note: Figure NOT drawn to scale

The above figure shows Square \(\displaystyle SQUA\)

\(\displaystyle SX = UY + 1\)

Which is the greater quantity?

(a) The area of Trapezoid \(\displaystyle SXYA\)

(b) The area of Trapezoid \(\displaystyle XQUY\)

Possible Answers:

(a) and (b) are equal

(b) is the greater quantity

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

(a) is the greater quantity

Correct answer:

(a) is the greater quantity

Explanation:

The easiest way to answer the question is to locate \(\displaystyle Z\) on \(\displaystyle \overline{SQ}\) such that \(\displaystyle SZ = UY\):

Square c

Trapezoids \(\displaystyle SZYA\) and \(\displaystyle ZQUY\) have the same height, which is \(\displaystyle SA = QU\). Their bases, by construction, have the same lengths - \(\displaystyle AY = ZQ\) and \(\displaystyle SZ = YU\). Therefore, Trapezoids \(\displaystyle SZYA\) and \(\displaystyle ZQUY\) have the same area.

Since \(\displaystyle SX = UY + 1\), it follows that \(\displaystyle SX = SZ+ 1\), and \(\displaystyle SX > SZ\). It follows that Trapezoid \(\displaystyle SXYA\) is greater in area than Trapezoids \(\displaystyle SZYA\) and \(\displaystyle ZQUY\), and Trapezoid \(\displaystyle XQUY\) is less in area.

Example Question #631 : Isee Middle Level (Grades 7 8) Quantitative Reasoning

Which is the greater quantity?

(a) The perimeter of a right triangle with legs of length 5 feet and 12 feet 

(b) 8 yards

Possible Answers:

(a) is greater

It is impossible to tell from the information given

(a) and (b) are equal

(b) is greater

Correct answer:

(a) is greater

Explanation:

The length of the hypotenuse of a triangle with legs 5 feet and 12 feet is calculated using the Pythagorean Theorem, setting \(\displaystyle a = 5, b=12\):

\(\displaystyle c = \sqrt{a^{2}+b^{2}} = \sqrt{5^{2}+12^{2}} = \sqrt{25+144} = \sqrt{169} =13\)

The hypotenuse is 13 feet long. The perimeter is \(\displaystyle 5 + 12 + 13 = 30\) feet, which is equal to 10 yards.

Example Question #241 : Geometry

Which is the greater quantity?

(a) The perimeter of a right triangle with hypotenuse of length 25 centimeters and one leg of length 7 centimeters

(b) One-half of a meter

Possible Answers:

(a) is greater

(b) is greater

It is impossible to tell from the information given

(a) and (b) are equal

Correct answer:

(a) is greater

Explanation:

The length of the second leg of the triangle can be calculated using the Pythagorean Theorem, setting \(\displaystyle a = 7,c =25\):

\(\displaystyle b = \sqrt{c^{2}-a^{2}} = \sqrt{25^{2}-7^{2}} = \sqrt{625-49}= \sqrt{576} = 24\)

The second leg has length 24 centimeters, so the perimeter of the triangle is 

\(\displaystyle 7 + 24 + 25 = 56\) centimeters.

One-half of a meter is one-half of 100 centimeters, or 50 centimeters, so (a) is greater.

Example Question #1 : Triangles

Which is the greater quantity?

(a) The perimeter of an equilateral triangle with sidelength 30 inches

(b) The perimeter of a square with sidelength 2 feet

Possible Answers:

(a) and (b) are equal

It is impossible to tell from the information given

(b) is greater

(a) is greater

Correct answer:

(b) is greater

Explanation:

Each figure has sides that are congruent, so in each case, multiply the sidelength by the number of sides.

(a) The triangle has perimeter \(\displaystyle 30 \times 3 = 90\) inches

(b) 2 feet are equal to 24 inches, so the square has sidelength \(\displaystyle 24 \times 4 = 96\) inches.

The square has the greater perimeter.

Example Question #2 : Triangles

\(\displaystyle \Delta ABC\) is an equilateral triangle; \(\displaystyle AB = 25\).

Rectangle \(\displaystyle RECT\)\(\displaystyle RE = 35\)

Which is the greater quantity?

(a) The perimeter of \(\displaystyle \Delta ABC\)

(b) The perimeter of Rectangle \(\displaystyle RECT\)

Possible Answers:

(b) is greater

(a) and (b) are equal

It is impossible to tell from the information given

(a) is greater

Correct answer:

It is impossible to tell from the information given

Explanation:

(a) The perimeter of the equilateral triangle is \(\displaystyle 25 \times 3 = 75\).

(b) \(\displaystyle CT = RE = 35\)\(\displaystyle EC, RT\) are of unknown value, but they are equal,  so we will call their common length \(\displaystyle N\).

Rectangle \(\displaystyle RECT\) has perimeter

\(\displaystyle 35 + 35 + N + N = 70 + 2N\).

Without knowing \(\displaystyle N\), it cannot be determined with certainty which figure has the longer perimeter. For example:

If \(\displaystyle N = 1\), then \(\displaystyle 70 + 2N = 70 + 2 \cdot 1 = 70 + 2 = 72 < 75\)

If \(\displaystyle N = 3\), then \(\displaystyle 70 + 2N = 70 + 2 \cdot 3 = 70 + 6 = 76>75\)

 

Example Question #2 : Triangles

\(\displaystyle \Delta ABC\) is an isosceles triangle; \(\displaystyle \Delta DEF\) is an equilateral triangle

\(\displaystyle AB = 30,BC = 50, DE= 35\)

Which is the greater quantity?

(a) The perimeter of \(\displaystyle \Delta ABC\)

(b) The perimeter of \(\displaystyle \Delta DEF\)

Possible Answers:

(b) is greater

It is impossible to tell from the information given

(a) and (b) are equal

(a) is greater

Correct answer:

(a) is greater

Explanation:

(a) As an isosceles triangle, \(\displaystyle \Delta ABC\), by definition, has two congruent sides. \(\displaystyle AB \neq BC\), so either :

\(\displaystyle AC = AB = 30\) 

in which case the perimeter of \(\displaystyle \Delta ABC\) is 

\(\displaystyle AB + AC + BC = 30 + 30 + 50 = 110\)

or

\(\displaystyle AC =BC = 50\)

in which case the perimeter of \(\displaystyle \Delta ABC\) is 

\(\displaystyle AB + AC + BC = 30 + 50 + 50 = 130\)

(b) \(\displaystyle \Delta DEF\) is an equilateral triangle, so, by definition, all of its sides are congruent; its perimeter is \(\displaystyle 35 \times 3 = 105\).

Regardless of the length of \(\displaystyle \overline{AC}\)\(\displaystyle \Delta ABC\) has the greater perimeter.

Example Question #231 : Plane Geometry

\(\displaystyle \Delta ABC\) and \(\displaystyle \Delta DEF\) are right triangles, with right angles \(\displaystyle \angle B , \angle E\), respectively. 

\(\displaystyle AB = 6,BC = 8, DE = 24, DF = 26\)

Which is the greater quantity?

(a) \(\displaystyle AC\)

(b) \(\displaystyle EF\)

Possible Answers:

(b) is greater

It is impossible to tell from the information given

(a) is greater

(a) and (b) are equal

Correct answer:

(a) and (b) are equal

Explanation:

(a) \(\displaystyle \overline{AC}\) is the hypotenuse of \(\displaystyle \Delta ABC\), so by the Pythagorean Theorem, 

\(\displaystyle \left (AC \right )^{2} =\left ( AB \right ) ^{2} + \left ( B C\right )^{2}\)

\(\displaystyle \left (AC \right )^{2} =6^{2} + 8^{2}\)

\(\displaystyle \left (AC \right )^{2} =36 + 64 = 100\)

\(\displaystyle AC = \sqrt{100} = 10\)

(b) \(\displaystyle \overline{EF}\) is a leg of \(\displaystyle \Delta DEF\), whose hypotenuse is \(\displaystyle \overline{DF}\), so by the Pythagorean Theorem, 

\(\displaystyle \left (EF \right )^{2} =\left ( DF \right ) ^{2} - \left ( DE\right )^{2}\)

\(\displaystyle \left (EF \right )^{2} =26^{2} - 24^{2}\)

\(\displaystyle \left (EF \right )^{2} =676 -576 = 100\)

\(\displaystyle EF= \sqrt{100} = 10\)

 

\(\displaystyle AC = EF\)

Example Question #243 : Geometry

Which is the greater quantity?

(a) The perimeter of a right triangle with legs of length 3 inches and 4 inches

(b) One foot

Possible Answers:

(a) and (b) are equal

It is impossible to tell from the information given

(a) is greater

(b) is greater

Correct answer:

(a) and (b) are equal

Explanation:

The length of the hypotenuse of a triangle with legs 3 inches and 4 inches long is calculated using the Pythagorean Theorem, setting \(\displaystyle a = 3, b=4\):

\(\displaystyle c = \sqrt{a^{2}+b^{2}} = \sqrt{3^{2}+4^{2}} = \sqrt{9+16} = \sqrt{25} =5\)

The hypotenuse is 5 inches long. The perimeter is therefore \(\displaystyle 3 + 4 + 5 = 12\) inches, which is equal to one foot.

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