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45-45-90 and 30-60-90 triangles
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An isosceles right triangle with angles 45°, 45°, and 90°.
Side Ratios:
In a 45-45-90 triangle, each leg has length 8. Find the hypotenuse.
In a 45-45-90 triangle, the hypotenuse = leg ×
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Where:
Key Pattern: If legs = 1, then hypotenuse =
Example: If each leg is 5, hypotenuse =
A right triangle with angles 30°, 60°, and 90°.
Side Ratios:
Where:
Key Pattern: If short leg = 1, then long leg = , hypotenuse = 2
Example: If short leg is 6, long leg = , hypotenuse = 12
45-45-90: legs equal, hypotenuse = leg ×
30-60-90: hypotenuse = 2 × short leg, long leg = short leg ×
Answer: (or approximately 11.31)
In a 30-60-90 triangle, the hypotenuse is 20. Find both legs.
In a 30-60-90 triangle, sides are in ratio
Hypotenuse = :
Short leg (opposite 30°):
Long leg (opposite 60°):
Answer: Short leg = , Long leg =
A 45-45-90 triangle has a hypotenuse of . Find the area of the triangle.
Step 1: Find the leg length
In 45-45-90 triangle: hypotenuse = leg ×
Step 2: Find area (both legs are equal)
Answer: Area = square units