Direct Proportion

The video tutorial explains the concept of direct proportion using various examples, such as painting a wall with different numbers of paint cans, the relationship between the radius and perimeter of a circle, and real-life scenarios like robot speed and map distances. It introduces the constant of proportionality and demonstrates how to calculate unknown values using proportional relationships.

If a painter uses 8 cans of paint, how many square feet of the wall can be painted?

• 72 square feet

• 64 square feet

• 80 square feet

• 90 square feet

What is the constant of proportionality if 2 cans of paint cover 18 square feet?

• 1/9

• 1/8

• 1/10

• 1/7

How many square feet can be painted with 15 cans of paint?

• 135 square feet

• 150 square feet

• 140 square feet

• 120 square feet

Is the radius of a circle directly proportional to its area?

• Yes, because the ratio is constant

• No, because the area decreases with radius

• Yes, because the area increases with radius

• No, because the ratio is not constant

How far will a robot travel in 15 minutes if it moves at 20 km/h?

• 10 kilometers

• 15 kilometers

• 5 kilometers

• 20 kilometers

How many packets of peanuts weigh 52.5 kilograms if 5 packets weigh 7.5 kilograms?

• 40 packets

• 25 packets

• 30 packets

• 35 packets

If the distance between two cities on a map is 6 cm, what is the actual distance if 5 cm represents 750 km?

• 900 kilometers

• 800 kilometers

• 850 kilometers

• 950 kilometers