Unit 2 Test Review 8th grade math

Rectangle A measures 12cm by 3 cm. Rectangle B is a scaled copy of Rectangle A. Select ALL measurements that could be Rectangle B.

• 6cm by 1.5cm

• 10cm by 2cm

• 13cm by 4 cm

• 80cm by 20cm

• 18cm by 4.5cm

Answer explanation

When we are talking about scale figures the ratio has to be the same. Since 12/3 = 4 then any scale drawing would have the same ratio.

Tags

CCSS.7.G.A.1

Which of these sets of angle measures could be the three angles in a triangle?

• 40, 50, 60

• 50, 60, 70

• 60, 70, 80

• 70, 80, 90

Answer explanation

The sum of the angles in a triangle has to be 180 degrees

Tags

CCSS.8.G.A.5

In the picture lines AB and CD are parallel. Find the measure of angleBCD.

Answer explanation

Since the lines are parallel we know that alternate interior angles are congruent.

Tags

CCSS.8.G.A.5

In the picture lines AB and CD are parallel. Find the measure of angleECF.

Answer explanation

Since the lines are parallel we know that alternate interior angles are congruent. Then we also know that vertical angles are congruent.

Tags

CCSS.8.G.A.5

In the picture lines AB and CD are parallel. Find the measure of angleDCF.

Answer explanation

Since the lines are parallel we know that alternate interior angles are congruent. Then we also know that a linear pair (two angles that make a straight line) have to add up to 180 degrees.

Tags

CCSS.8.G.A.5

Segment AB meausres 3cm. Point O is the center of dilation. How long is the image of AB after a dilation with scale factor 5?

Answer explanation

When dilating by a scale factor then we know that all segment measures are multiplied by the scale factor.

Tags

CCSS.8.G.A.3

Segment AB meausres 3cm. Point O is the center of dilation. How long is the image of AB after a dilation with scale factor 3.7?

Answer explanation

When dilating by a scale factor then we know that all segment measures are multiplied by the scale factor.

Tags

CCSS.8.G.A.3

Segment AB meausres 3cm. Point O is the center of dilation. How long is the image of AB after a dilation with scale factor 1/5?

Answer explanation

When dilating by a scale factor then we know that all segment measures are multiplied by the scale factor.

Tags

CCSS.8.G.A.3

Segment AB meausres 3cm. Point O is the center of dilation. How long is the image of AB after a dilation with scale factor s?

Answer explanation

When dilating by a scale factor then we know that all segment measures are multiplied by the scale factor.

Tags

CCSS.8.G.A.3

Triangle ABC is a scaled copy of triangle DEF. Side AB measures 12 cm and is the longest side of ABC. Side DE measures 8 cm and is the longest side of DEF. What is the scale factor to go from triangle ABC to triangle DEF?

Answer explanation

When determining scale factor always do image divided by preimage for corresponding sides.

Tags

CCSS.7.G.A.1