Mathematics 7

# Surf for More Math

## Lesson 3 - Calculating the Area of a Triangle

Use these interactive activities to encourage your child to have fun on the Web while learning how to calculate the area of a triangle.

### Goal

Explore the area of a triangle on a geoboard.

### Builds Upon

Student Book page 160

### Instructions for Use

Touch Pegs prompts your child to investigate how length and width relate to area.

To use Touch Pegs, select a blue band under "Bands" then drag it to any location on the grid. Release the band to anchor it. A red node appears at the top of the band. Click on any part of the band and drag it in any direction. It will stretch like a rubber band. Release the band to secure it to a point on the grid. Secure the band to another point on the grid to form a triangle.

To change a vertex of the triangle, release a node by holding down the "Ctrl" key and clicking the node. To colour the area inside the triangle, click on the triangle and then click one of the colour buttons to the left of the grid.

Calculate the area of the triangle you created. Click the "Measure" button to check your answer. Click on the "Clear" button to start the exercise over again.

Triangle Explorer prompts your child to investigate and calculate the area of a triangle.

To use Triangle Explorer, click the “New Triangle” button. Determine the area of the triangle and input the answer into the text field. Click the "Check Answers!" button to check the answer. If your child is unsure of the answer, suggest that he or she click the "Give Hint" button to provide help.

Calculating the Area of a Triangle helps your child practice multiplying base by one-half the height to find the area of a triangle.

To use Calculating the Area of a Triangle, click the "Start" button. Based on the base and height measurements given, input the area of a triangle in the text box. Click the "Check" button to check the answer.