Evaluating expressions with and without changing the subject

12 questions

1. Substitute means to put in place of another. In algebra, substitution can be used to replace __________ with values.
2. A={1\over2}(a+b)h is the formula for area of a trapezium. It can be rearranged to {2A\over{h}}-a=b in order to make b the ___ of the formula.
3. The formula for area of a triangle is A={1\over2}bh. The area of a triangle with base 7.5 cm and height 6 cm is ___cm²
4. The formula s={d\over{t}} can be rearranged to t={d\over{s}} or d=s\times {t}. If d=12 and s=3, find t.
5. Find the area of a trapezium with h=7, a=3.2, b=4.8.
6. A={1\over2}(a+b)h is the formula for area of a trapezium. Select all the correct rearrangements of this formula.
7. a=\sqrt{{c^2}-b^2} is a __________ of a^2+b^2=c^2.
8. Which arrangement of the formula for area of a triangle makes it quickest for you to find b if you know A and h?
9. The formula for the area of a triangle is A={1\over2}bh. The base b of a triangle with area 24 m² and height 8 m is ___m.
10. Rearrange the formula C=2{\pi}{r} to find the radius of a circle with circumference 42 cm. Leave your answer in terms of \pi.
11. Which rearrangement makes it easiest to find length b if you know lengths a and c?
12. Jun says "You have to rearrange the formula a^2+b^2=c^2 into the form b=\sqrt{{c^2}-a^2} with b as the subject if you want to find b given that a=6 and c=10." Is Jun right?

License: OGL