Question

$\Delta$ ABC is right-angled at B, with AB = 7 cm and AC - BC = 1 cm. Which of the following is correct?

• A. sinA = 7/25
• B. sinC = 7/24
• C. cosA = 24/25
• D. cosC = 24/7
• E. cosC = 24/25

Answer 1

The correct option is E

cosC = 24/25

Using the Pythagoras theorem, we have -

(x + 1)${}^2$ = 7${}^2$ + x${}^2$ $⟹$ x = 24.

Thus, BC = 24 cm and AC = 25 cm.