Reading Line Graphs

Show your work for each problem.

1.
Which axis on a line graph usually shows time?
1. a)Title
2. b)Y-axis (vertical)
3. c)X-axis (horizontal)
4. d)Z-axis
Answer: X-axis (horizontal)
The X-axis (horizontal) typically shows time in a line graph, while the Y-axis (vertical) shows the measured values.
2.
If a line on a graph goes upward from left to right, what does it show?
1. a)The values stay the same
2. b)The values are increasing
3. c)There is no data
4. d)The values are decreasing
Answer: The values are increasing
A line going upward from left to right indicates that the values are increasing over time. This is called an upward trend.
3.
A line graph shows temperatures: Monday 12°C, Tuesday 15°C, Wednesday 18°C. What is the temperature on Tuesday?
Answer: 15
Looking at the data, Tuesday shows 15°C. To read a line graph, find the day on the X-axis and look at the corresponding value.
4.
A line graph shows website visitors: Day 1: 200, Day 2: 250, Day 3: 300. How many more visitors were there on Day 3 than Day 1?
Answer: 100
. There were 100 more visitors on Day 3 than Day 1.
5.
What does a flat (horizontal) line on a graph indicate?
1. a)No change in value
2. b)Rapid decrease
3. c)Missing data
4. d)Rapid increase
Answer: No change in value
A flat (horizontal) line means the value stays the same over that time period. There is no increase or decrease.
6.
A line graph shows daily book sales: Monday 40, Tuesday 55, Wednesday 35, Thursday 60, Friday 50. Find the highest and lowest sales days and calculate the range.
Answer: 25
1. What is the highest number of books sold? 60
2. Which day had the highest sales? Thursday
3. What is the lowest number of books sold? 35
4. Calculate the range: highest - lowest 25
7.
A line graph shows temperature changes: 8 AM: 14°C, 10 AM: 18°C, 12 PM: 22°C, 2 PM: 24°C. Describe the trend and calculate the total change.
Answer: 10
1. Is the line going up or down overall? up
2. What is the starting temperature at 8 AM? 14
3. What is the ending temperature at 2 PM? 24
4. Calculate the total change: 10
8.
A line graph shows plant height over weeks: Week 1: 5 cm, Week 2: 8 cm, Week 3: 11 cm, Week 4: 14 cm. By how many centimeters does the plant grow each week?
Answer: 3
Week 2 - Week 1 = cm. The pattern is consistent: the plant grows 3 cm each week.
9.
A line graph shows test scores over 4 weeks: 65, 70, 68, 75. Between which two weeks did the score decrease?
1. a)Week 1 to Week 2
2. b)No decrease occurred
3. c)Week 3 to Week 4
4. d)Week 2 to Week 3
Answer: Week 2 to Week 3
The score went from 70 (Week 2) to 68 (Week 3), which is a decrease of 2 points. All other changes were increases.
10.
A line graph shows rainfall in mm: Mon 4, Tue 8, Wed 6, Thu 10, Fri 2. What is the average daily rainfall?
Answer: 6
Average = mm per day.
11.
A line graph shows ice cream sales: June 120, July 180, August 200, September 150. In which month were sales highest? Calculate how much more was sold in the peak month compared to June.
Answer: 80
1. Which month had the highest sales number? August
2. What were the sales in August? 200
3. What were the sales in June? 120
4. Calculate the difference: 80
12.
A line graph shows two students' reading pages per day. Student A: Mon 15, Tue 20, Wed 25, Thu 30. Student B: Mon 25, Tue 25, Wed 25, Thu 25. Compare their trends and find who read more pages total.
Answer: B
1. What is Student A's trend? (increasing, decreasing, or flat) increasing
2. What is Student B's trend? flat
3. Calculate Student A's total: 90
4. Calculate Student B's total: 100
5. Who read more pages total? (A or B) B
13.
A line graph shows a steep rise followed by a gradual decline. Which real-world situation could this represent?
1. a)Temperature rising in morning then cooling in evening
2. b)Age increasing over years
3. c)Constant heart rate during rest
4. d)A plant growing steadily taller
Answer: Temperature rising in morning then cooling in evening
Daily temperature typically rises quickly in the morning and then gradually cools in the afternoon and evening, matching a steep rise followed by gradual decline.
14.
A line graph shows scores: Game 1: 85, Game 2: 92, Game 3: 78, Game 4: 95, Game 5: 88. If the pattern of the last 3 games (down, up, down) continues, predict Game 6's approximate score.
Answer: 95
The pattern shows down-up-down (78→95→88). Following this, Game 6 should go UP. Looking at similar increases, it would likely return to around 95.
15.
A line graph shows pool water temperature every 2 hours: 6AM: 20°C, 8AM: 22°C, 10AM: 26°C, 12PM: 30°C, 2PM: 32°C, 4PM: 30°C. When was the temperature rising fastest? Calculate that rate of change.
Answer: 4
1. What is the change from 6AM to 8AM? 2
2. What is the change from 8AM to 10AM? 4
3. What is the change from 10AM to 12PM? 4
4. What is the change from 12PM to 2PM? 2
5. Which time period had the largest increase (in °C per 2 hours)? 4