How to use proportions for an isosceles triangle

The video tutorial explains how to solve for X in an isosceles triangle by setting up and solving proportions. It highlights common mistakes, such as incorrect proportion setup, and demonstrates the use of cross products. Alternative methods for writing proportions are discussed, emphasizing the importance of consistency. The tutorial concludes with solving the equation to find the value of X.

What is a key characteristic of an isosceles triangle?

• It has a right angle

• All sides are equal

• Two sides are equal

• All angles are equal

Why is it incorrect to set the proportion as 4 is to X + 5 in this problem?

• Because 4 is not a side of the triangle

• Because X + 5 is not a valid expression

• Because it results in a quadratic equation

• Because it does not use the third side for proportion

Which method is used to solve the proportion in this problem?

• Cross-multiplication

• Substitution

• Elimination

• Graphing

What is the value of X after solving the proportion?

• 5

• 6

• 7

• 8

What is the first step in solving the equation 36 = 3X + 15?

• Divide both sides by 3

• Subtract 15 from both sides

• Add 15 to both sides

• Multiply both sides by 3