An ideal gas. Cp = (7 / 2) R and Cv = (5 / 2) R, undergoes

Question:

An ideal gas. Cp = (7 / 2) R and Cv = (5 / 2) R, undergoes a cycle consisting of the following mechanically reversible steps:
• An adiabatic compression from P1, V1. T1 to P2, V2, T2.
• An isobaric expansion from P2. V2, T2 to P3 = P2, V3. T3,
• An adiabatic expansion from P3. V3. T3 to P4, V4, T4.
• A constant-volume process from P4, V4, T4 to P1, V1 = V4, T1.
Sketch this cycle on a P V diagram and determine its thermal efficiency if Ti - 200 C, T2 = 1000 C. and 7*5 = 1.700 C?