Answer:
a. 75 m
Explanation:
Given,
Length of hypotenuse = 18m
Length of perpendicular = 10 m
To find:
Area of the right angled triangle
Formula to find area of the right angled triangle =

To find: Length of base
Hypotenuse² = Perpendicular² + Base²
Base² = Hypotenuse² - Perpendicular²
Base² = 18² - 10²
Base² = 324 - 100
Base² = 224
Base =

Base = 14.97 m
Area of the right angled triangle =

⇒

⇒ 74.85 m² or,
round to the nearest tenth = 75 m²